Grenade Hot Potato

In reality, picking up an armed grenade that has been thrown in your general direction is a really bad idea. But in the world of TV, videogames, and fiction-land, there's just enough time for the heroes to play a game of Grenade Hot Potato, a deadly and dangerous version of regular Hot Potato. They can toss it back (extra points for blowing up the original thrower), pass it to someone else to deal with it (which leads to them realizing they've just been handed a live grenade and try to pass it onto someone else) or, in the more heroic fashion for when the clock is really low, jump on it.

In reality, different types of grenades have different fuse times. Some grenades are meant to be thrown in a high arc, and throwing them wrong might leave the enemy time to respond. Other grenades are designed with short, or even no, fuse time (the latter are mostly intended for use in traps). Generally, it's a bad idea to use a grenade unless you know what type it is and have been trained in its use.

Just one possible form of Playing Tennis With the Boss and a subtrope of Catch and Return. When used in Darker and Edgier stories, or when the "hero" happens to be wearing a Red Shirt, it tends to backfire horribly.

Examples of Grenade Hot Potato include:

Anime and Manga

In Black Lagoon, Mr. Chang demonstrates that if you are cool enough, you can toss a grenade right back at the thrower without even having to pick it up.
During one Gundam X episode, as the heroes are fighting on foot, enemy soldiers throw a grenade at them. One of the heroes shouts "You threw it too early!" and kicks it back, blowing up the soldiers they were fighting.

Film

The climax of the original Tremors movie.
The Punisher movie has a grenade sent back to the thrower... via baseball bat.
In Saving Private Ryan Mellish manages to get rid of two German grenades this way. To be fair, they landed in his lap while he was trying to unjam his rifle, he didn't have much of a choice. A German soldier also pulled this off with an Allied grenade.
Stitch and Jumba in Lilo and Stitch do this with a malfunctioning plasma gun. As they toss it back and forth, they actually say "One potato, two potato..."
In You Don't Mess With the Zohan, Zohan parodies this by using a grenade for a tennis ball.
A major character in The Bridges At Toko-Ri throws back the first grenade thrown at him. Then the second grenade. Then tries to throw back the third grenade. Cue Gory Discretion Shot.

Literature

In the Modesty Blaise short story "A Better Day To Die" (part of the Pieces Of Modesty collection), Modesty is attempting to protect a missionary with no combat skills from a gang of bandits. The missionary ends up demonstrating the cricketing skills he had mentioned earlier by making a diving catch of a Mills bomb and throwing it back at the bandits in the manner of a slips fieldsman, with lethal results.
Happened in a Dear America book set in the Vietnam War. A Vietcong grenade lands near the narrator and fails to go off. He throws it back and takes a bullet for his troubles ... in his canteen.

Live Action TV

Monk didn't toss one back, but did pick one up to put in a fridge.
- Then he reopened the fridge and neatly set it in the egg holder.
On MythBusters, they explored several ways to deal with a nearby grenade, including throwing it in a bucket of water or into a fridge (as per the previous example). Most were ineffective but was shown that training soldiers to throw themselves on a grenade is in fact, an effective way to reduce casualties, since each grenade only kills one person, and the human body is a better shield against fragmentation grenades than most other common objects lying around on a battlefield.
- A bucket of water would also work fairly well, though the bucket might hurt somebody if it hit them, the water dissipated most of the blast.
In Malcolm in the Middle, Reese and his grandfather plays grenade hot potato after the pin is accidentally pulled from one of their grandfather's World War Two souvenirs. The grenade ends up being disposed of in the fridge.
Played With in an episode of a British TV Series called Bernards Watch. Bernard's Grandad is showing him some WW 2 antiques including a grenade pin, the rest of the grenade drops out of a coat so Bernard stops time, takes the grenade outside, drops it in the park, goes back home and restarts time so the grenade can explode safely.
On Lost, when the Others throw a grenade at Keamy, he has just enough time to kick it away... and kill his buddy Omar.

Professional Wrestling

Chuck Taylor in CHIKARA pantomimes pulling out and using a grenade against his opponents (stay with us here). Occasionally it'll work as intended, that is, his opponent, but it has been turned against him in predictably cartoonish ways (as well as being Soldier Ant's Crowning Moment of Awesome).

Video Games

In Call of Duty 2, NPCs would often throw back grenades, and they would never blow up in their hands unless the player "cooked off" the grenade before hand. In Call of Duty 3 and Modern Warfare onwards, the player could do the same... but lacked the same luck/invulnerability/TheComputerIsACheatingBastard. Attempting this in multiplayer usually results in getting blown up, due to the fact that most everyone cooks frags before they throw them. Certain perks (Toss Back in World At War and Flak Jacket Pro in Black Ops) reset the fuse on a picked-up grenade, preventing this problem.
- Grenades can blow up in the hands of NPCs, even without being cooked. (The AI does have an edge, though)
- Ditto for the Medal of Honor series.
This is possible in Half Life 2, with or without the Gravity Gun. In Episode Two, pulling it off earns you an Achievement.
In X-COM: Enemy Unknown, only a little coordination and preparation is needed to perform a Grenade Relay.
One of the minigames in a Mario Party game is this trope outright, with the series's native Bob-ombs as the potatoes in question.
BioShock (series) lets you do this with the Telekinesis plasmid with any grenades or molotov cocktails. It's pretty effective, too.
A minigame in Yoshi's Island has you playing catch with an enemy using a slowly expanding balloon. You have to make sure not to be holding it when it pops.
In Wild Guns, you can pick up enemies' thrown dynamite and toss it back at them. Your character puts out the fuse when they pick it up, so there's no worry of the dynamite blowing up on them.
Magicka has both bomb-throwing goblins and arrow-firing ones, and both projectiles can be deflected, or if you're lucky returned with the default staff puff-pushback.
In the Touhou fighting games, Marisa has both a special move (Magical Recycled Bomb) and a super move (Deep Ecological Bomb) that make her throw pots of charging magic energy. They can be hit back toward her if her opponent is canny.
Can be done in Halo if you're sufficiently skilled or lucky. To "return to sender" a grenade, you have to throw a sticky (plasma or spike) on it; this changes the direction of the grenades, as the last force was your throw, allowing both to hit the original thrower(who'll probably call you a hacker).
Spec Ops: Red Mercury. The enemies can, and will, run out of cover, catch a grenade you've thrown and throw it right back at you. Oh yeah, did I mention they can catch TWO grenades at once?

Web Comics

Girl Genius in one of the first mini-arcs had Gilgamesh batting a flying grenade back at its thrower.
- And was later chastised because the grenade annihilated said thrower.
Schlock Mercenary Book 11 had a moment when Nick scooped an incoming grenade and swatted it away. To the place where an explosion strands his entire team in the middle of an enemy fortress.

Western Animation

The Spectacular Spider-Man episode "Subtext" uses a Grenade Hot Potato in the form of one of Gobby's Pumpkin Bombs.
Shows up often in classic cartoon shorts such as Looney Tunes and Tom and Jerry. Though in these cases, it's usually a stick of dynamite or a Cartoon Bomb.
In Futurama with a bomb that was programmed wrong, leading to Leela stating "Hey be careful with that. You could put someones eye out".
In the "Final Fight" episode of the Street Fighter cartoon, when Rolento threw his grenades, Guy caught them, JUGGLED THEM, and then threw them back at Rolento. Rolento was so shocked by Guy's skill that he didn't even move out of the way.
Wile E. Coyote and Bugs Bunny do this in a Looney Tunes short.
In the Archer season 3 "Heart of Archness", when his pirates turn against him, Archer is holed up in a fortress, and during Casual Danger Dialogue he is catching grenades with a butterfly net and tossing them back. He used the net earlier in the episode as a lacrosse stick.
Happens between Robin, Batgirl, and Harley in the DC Super Hero Girls episode "#GothamCon", where all three are trying to get rid of Harley's ill-placed bomb. Several times, they find a place to dispose of it, only to realize said place has something they do not want destroyed. Harley finally solves the problem with a fire extinguisher - but can't resist trolling Batgirl by spraying her in the face with it.

Real Life

Real grenades tend to have unpredictable fuses, making this trope much more dangerous than in fiction. This also makes 'cooking' the grenade a bad idea - SOP is generally to throw the thing as quickly as you can and get the f*ck away if one comes knocking. In foxholes, having a grenade sump or water bucket that grenades can be tossed into to absorb the blast in is generally substituted for putting yourself in even more danger.
During the battle of Tarawa (WWII), one of the marines threw back two grenades tossed by the Japanese, catching them in mid-air. When he tried for a hat-trick, the third grenade promptly blew up in his hand.
An Australian-Canadian-Brit (it's complicated), Lance-Corporal (later Lieutenant) Leonard Keysor, won the Victoria Cross during the Battle of Lone Pine (WWI) for continually doing this with Turkish grenades over a period of 50 straight hours
Sergeant First Class Leroy Petry picked up a grenade, and attempted to throw it away from himself and several other soldiers. It detonated as he released it, causing him to lose his hand, and earn a Medal of Honor.
Actual PLA training exercise.