Commercial Switcheroo

The commercial equivalent of the Show Within a Show. You're watching a commercial for a very generic product -- the commercial may even be so laden with blatant Advertising Tropes that it doesn't seem quite real.

This is because it isn't. The action will shortly be interrupted by... another commercial! Zapulix-Brand Aspirin was just a red herring!

Probably meant to convey that the product is so great that it can just stomp all over other commercials. Also, the fake commercial will usually lampoon normal commercial devices, so it may give the producers of advertising some relief from the normal soul-crushingness of their existence.

Similar to Trailer Spoof, but usually without trying to parody any specific real product. Not to be confused with a Product Switcheroo Ad.

Banking

 * VISA filmed several ads for real vacation resorts, which mentioned at the end that you should bring your VISA card, since the place doesn't accept American Express.
 * The irony is that most of the hotels featured, when asked by an independent survey, revealed that most of them either had never stopped offering American Express, or had done so (briefly) in favor of VISA, but quietly started taking American Express again afterward.

Cars

 * The ads for the Vauxhall Insignia start out looking like trailers for a movie, or possibly a new TV show. "The Insignia Project". Something like a cross between James Bond and 24.
 * Used with a real product in one car commercial, where actual footage from an ad for Snuggies (overpriced coat-shaped blankets) was cut off by a guy with an axe chopping through the TV screen and revealing an SUV... The kicker is that the actual snuggie commercial played around the same time.
 * The second version was easier to spot. It used an original ad for the "Lap n' Snack", a weird-shaped plastic bowl that would have rested on your knee. Since nobody had seen it before, after seeing the commercial once they knew what it was.

Eyewear

 * Hundreds, if not thousands, of bikini clad women run enthusiastically toward a pasty plain guy who is anointing himself in bodyspray; think it's another Lynx/Axe ad? Nope. All the woman immediately stop as soon as he puts on his hideous spectacles... "Should've gone to Specsavers"

Food and Drink

 * Sprite frequently pulled this trick during their "Obey Your Thirst" ad campaign, usually by starting out as ads for non-existent, "hip" drinks, such as "Jooky".
 * Jooky! Jooky! It's a party in a CAHN!
 * Five words: Car, meadow... ZOMBIE!! K-Fee Coffee.
 * Happens in recent Australian ads for lamb: one was a trope-laden ad for perfume, and another an ad for a really cheesy romantic comedy. Except that they're ads for lamb (or, rather LÂMB, "the fragrance for spring", and Falling in Lamb)
 * An eighties commercial for Picnic chocolate bars was made up of generic shots of nuts, caramel and raisins falling across the screen, while a voiceover said, "There are so many good things in a Picnic bar, we can't fit them all in this advert." Cut to a laundry detergent commercial with a woman waxing lyrical about her new whiter-than-white clothes - only to get drenched in a downpour of chocolate. The voiceover smugly adds, "So we put the chocolate in this one."
 * Similar to the Energizer bunny one below, an eighties British advert for Carling lager starts off with the advert for the lager, and then carries on with fake adverts that are crashed through by the characters from the first ad.
 * In one Trix commercial from the mid 90s, the Trix rabbit disguises himself as a human, and actually manages to obtain a box of Trix. He then goes to the fridge to put milk on it, and discovers that he doesn't have any. It's actually a "Got Milk?" commercial.

Household

 * Popularized if not invented by the Energizer Bunny commercials. A battery powered toy rabbit, initially created for a straight commercial, wanders off the set, due to the unstoppable powers of the Energizer battery. The rabbit wanders through other advertisements, interrupting them as the Energizer voice-over guy announces "It keeps going, and going, and going..."
 * Created for a straight commercial by a competitor, no less! Duracell ran a series of commercials in The Eighties in which the Duracell-powered bunny was the Last Man Standing out of ten or so such toys. Energizer's version was a Take That that really caught on.
 * The bunny also rampaged through famous movies as well Hilarity ensued.
 * Pilkington Self-Cleaning Glass Conservatories adverts start off as a very cheesy Infomercial/ShoppingChannel parody seemingly from The Eighties advertising some awful product intended for use in a conservatory. They the switch to a silently amused conservatory owner who turns to admire their conservatory glass with a voice over saying something like "If you want a useful invention try Pilkington Self-Cleaning Glass".

Hygiene Products

 * There is a banner ad for a deodorant that has a fist made of deodorant residue come out of a woman's arm, snake across the article you're reading and punch a man in an apparently unrelated teeth-whitening ad in the face.
 * Old Spice Body Spray is too powerful to stay in its own commercial!

Insurance

 * Nationwide Insurance featured a Super Bowl commercial which, at first glance, appeared to sell a cologne endorsed by every housewife's fantasy, Fabio. Basically, he's rowing a gondola with a woman in it as this ad extols the virtue of his cologne. Then, he passes under a bridge, and bam! He becomes old and disheveled, and we learn that "life comes at you fast".
 * A Progressive Insurance commercial even interrupts one of their other commercials.
 * Other examples are rare, but there is good news. I just saved a bunch of money on my car insurance by Switching to GEICO!
 * GEICO ran a fake-trailer for a reality show called "Tiny House" before revealing itself as a GEICO ad. The trailer was well done, and real reality show premises can be just as stupid, so it was quite convincing. Here it is. (video is now just a still image)
 * And let's not forget this one

Medicine

 * Alka-Seltzer had one very famous ad about a meatball commercial being shot where the actor repeatedly blew his line "That's a spicy meatball!" Since he had to take a bite from those spicy meatballs on each take, he soon needed some Alka-Seltzer before he could continue.
 * The irony here is that most people started looking for Mama's Meat Sauce and couldn't find it anywhere while completely ignoring the Alka-Seltzer.

Movies

 * A trailer for ResidentEvil: Apocalypse begins with an at first prosaic, then progressively frightening, commercial for a beauty product. This is also a bit of world-building, as the product's manufacturer was the amoral pharmaceutical conglomerate from the games, Umbrella Corporation.
 * And the sequel featured an ad for a Vegas vacation, which then skipped, repeated, and panned out, revealing the famed Strip, along with the rest of the city, covered in desert.
 * MTV played a promo for Asher Roth's album, then suddenly the background behind Asher looks like it's giving away, and then it fizzles into a promo for the new Star Trek movie, then background with Asher Roth rapping comes back like nothing happened.
 * MTV has done it again, they played the usual ad for Americas Best Dance Crew which suddenly get interrupted by Freddy Krueger (either his clawed hand or a ghostly face) and the ad turns into a commercial for the upcoming Nightmare On Elm Street remake, then suddenly it goes back to the end of the ABDC ad.
 * Hilariously done on IMDB where they frequently have those banner ads where people dance for no reason about insurance or whatever. In one of them, Michael Myers suddenly came in and dragged one of the dancers away, revealing it as an ad for Halloween 2.
 * USA once interrupted their scheduling bumpers with ads for the movie Hop.
 * Disney's Lilo and Stitch movie had four ads that would start with a classic Disney movie, such as Aladdin and Beauty and the Beast, followed by Stitch interrupting the moment.

Pest Control

 * Orkin did a number of commercials like this in which a wayward insect would wander over the top of another commercial before the exterminator could kill it. Legends abound about people freaking out and smashing their screens in an attempt to kill what they thought was a real bug.
 * Orkin discontinued those commercials because of a lawsuit after a man threw his shoe at the tv because of one such commercial.

PSA's

 * During the late '90s, Ad Council ran a series of PSAs that ended with a character being exhausted after rather minimal physical activity, followed by the announcer saying "Excercised lately?" and the tagline "Get up. Get out." One of them started out as a fake ad for "Gofer Cakes", which looked more or less like mini whoopee pies. The excited kids in the ad end up lying on the floor, too full and sugar-crashed to move. Don't ask why this was a PSA for getting more exercise (the kids seemed to have plenty of energy at first) rather than not eating too much junk food.
 * Another PSA started out looking like a perfume commercial with a lovely model in a fancy house with beautiful music playing. Then we see the bottle of perfume which rotates to reveal its name: Breast Cancer. The model is visibly shocked and the announcer even apologizes for getting your attention this way.
 * A rather heart-breaking anti-smoking PSA starts out as a trailer for a dramatic movie about a man who has to give away his daughter at her wedding. Near the end, the camera pulls back to reveal this commercial displayed on a television in a hospital room. The patient and his adult daughter watch with sadness. The implication is that due to the father's (apparently smoking related) illness, he won't live to give away his daughter at her wedding.

Restaurants

 * A recent ad for Jack in the Box begins as a commercial for a car that runs on water and produces no harmful emissions, which is interrupted by Jack, the restaurant's CEO mascot, introducing a new sirloin steak sandwich. Having completed his pitch, the piece returns to the presenter of the car ad, who says "Really? Sirloin?"
 * Western New York food chain Mighty Taco is fond of these.n (video Removed) "Your gold is worth its weight in tacos!"
 * A driver is in a crash. He presses a little button above his head and starts talking with an operator, who calls an ambulance. Typical On Star ad, so far. The driver then asks the operator to do him a favor: call Jimmy John's, the sandwich delivery company.
 * You can call me Nannerpus, Nannerpus, and guess what, I love panc--
 * Boston Market did a whole series mimicking other commercial genres, right up until they announced what they were advertising. One was designed liked a cleanser ad ("I had splitter-splatter all over my kitchen, but now it's always sparkling clean. What's my secret? Boston Market!") another like a painkiller ad ("Tension headaches are the worst. Fortunately, now there's solution: Boston Market"). They all had the same tagline: 'We're cooking up dinner so you don't have to'.

Television

 * There's an ad for a home makeover show that started by pretending to be a standard "game" banner ad.
 * The Secret Saturdays began life as a series of "home video"-style ads featuring cryptids showing up in a typical urban situation, which were soon followed up by ads for an upcoming "Weird World" series. Eventually, these ads revealed their true colors; about halfway through the Weird World commercial, the camera zooms out to reveal one of the characters watching the ad to allegedly gain inside information on the series' Big Bad, who was not-coincidentally the person apparently hosting Weird World
 * There was a commercial for a new sitcom called "Zombie Dad" on Space.. it actually looked pretty fun, until it ended up being a network ad for Space saying you don't have to watch such awful shows.
 * The British satellite channel UK Gold (which has since been renamed a few times) had a surprisingly well-made series of ads in this vein advertising supposed comedy or drama shows that weren't good enough to make their schedule. For example, a show about two British coppers called George Tea and Alan Biscuits being lent to a police force in America, called "Tea and Biscuits", and a comdey called "Stuntman Husband", which was about a guy who had a job as a stuntman, and often performed stunts in his everyday life.
 * They also had a series showing supposed foreign remakes of British comedies, such as an American version of The Royle Family, an Australian version of The Vicar of Dibley and a Japanese version of Only Fools and Horses.
 * Direct TV. It starts out with a clip of an interesting movie, then a movie fan briefly interacts with the characters. The idea is that with Direct TV the viewer has much more control over when and where things start. Sadly, the interesting movies are not real.

Toys

 * The commercial for the Power Jet from Captain Power and the Soldiers of the Future starts as a generic cake mix commercial, hijacked by Captain Power.

Coupons

 * Groupon caught some flak for this; Their 2011 Super Bowl ad started out like an ad for a charity to help out Tibet... then switched gears to talk about how the announcer got 50% off Tibetan food thanks to Groupon. Many thought this was in bad taste, which made it the most talked about ad that year.

Cellphone

 * A recent series of Tesco Mobile ads in the UK centred around a group of people wishing for "a world where strangers... become friends" etc, before cutting to a simple person on a white background asking simply for a cheap monthly rate with a free phone.

Live-Action TV

 * Monty Python's Flying Circus managed to change courses twice in a Parody Commercial. Propaganda extolling "American defense" uses diagrams of tooth decay to represent Communist infiltration, which turns out to be part of an advertisement for Crelm Toothpaste. A cartoon automobile race follows, comparing the effectiveness of Crelm Toothpaste to an unspecified other brand, which quickly segues to a pitch for Shrill Petrol. In this advertisement, a white card representing engine deposits is displaced by a black card representing an Idiosyncratic Wipe to the next sketch of the show.
 * Saturday Night Live took it further, with a pitchman who wandered through half a dozen commercial settings, repeatedly implying what the ad was about but switching before mentioning a product. At the end, he goes home without mentioning any product at all. Cue announcer: "This message brought to you by The Ad Council: Wasting your time in various ways for no good reason."

Radio
""She knows that flyaway hair needs a little extra body..." "Yes! If you've got a little extra body, why not bring it to Stiffco!""
 * The Burkiss Way featured spoof ads as part of an 'intermission' on almost every episode. In later series a running gag developed where the spoof ads, no matter what they seemed to be parodying, would actually turn out to be for Stiffco Funeral Services.