Onrushing Army

In this popular subset of Hollywood Tactics, an army lines up in a large rectangular formation at one end of a huge field. When the battle begins, they charge forward, screaming at full volume until they collide against the opposing force or fortification.

The opposition, likely as not, will form their own line and rush forward at the same time, so that the two meet (with a satisfying crunch) in the middle of the field. All semblance of formation or military discipline will immediately vanish as the warriors engage one another individually. Don't expect any tactical maneuvres such as flanking or use of reserves, or for anyone to take advantage of the terrain or try to move to the high ground. If there are any cavalry, they will not form up together and try to outmaneuvre anybody but just run in front of the infantry.

If one side doesn't charge, they will hold their line and fire at the approaching force with whatever artillery they have until the last moment, which makes little more sense than running amok. Rarely, one side will have some kind of fortification, be it a trench or a castle, against which a charge is especially stupid and almost certain to fail, unless someone breaks out ladders and battering rams.

This trope may have some basis in trench warfare, which peaked at the end of the industrial age and was quickly discredited when technological advances rendered it horrifically ineffective. A casual glance at the mortality figures of World War I (~9 million) will show you how well it worked against advanced firearms. Even before guns, this tactic was exceedingly rare, and even ancient barbarians generally knew better than to just gang up and run toward the enemy. On the other hand, this tactic is similar to a Zerg Rush, which can be viable if you have lots of combatants to spare and, usually, the element of surprise.

Realism aside, this trope makes for a useful and iconic image for filmmakers, and is popular in an introductory scene as a way to quickly tell the audience that these two large groups of people really, really don't like each other.

Comic Books

 * Asterix does it regularly with the roman army and that both in internal conflicts and against whoever they are fighting in the given album.

Film

 * The Prologue of The Lord of the Rings film featuring mindlessly rushing Orcs against more disciplined Elves. The final battle between Aragorn's force and the combined, very much larger force of Mordor plays this trope even stronger.
 * Used to a T in The Chronicles of Narnia: Prince Caspian. The Telmarines send their cavalry in first, far ahead of the infantry, charges far ahead, then monolithic rectangles of infantry slowly walk in, supported only by trebuchets.
 * Braveheart plays with this. There are Screaming Warrior charges, sure, but there's also archers, cavalry, and Irishmen deployed in various battles before they get to that bit.
 * The Spartans do this in 300 whenever they don't feel like using a phalanx as they're supposed to.
 * Big Trouble in Little China. The Chang Sing and Wing Kong secret societies line up facing each other (a "Chinese Standoff"). When one of the Wing Kong members yells, they charge to attack each other. Watch it here, starting at 1:30.
 * Done in The Mummy Returns. We see lots of this trope in flashback, and toward the climax it's also done with the Medjai versus the army of Anubis. Partially justified, since Anubis warriors are dog-headed monstrosities and possibly not smart enough to use strategy.

Literature

 * On the Discworld, this is the policy of the D'regs. As their wise man said in Jingo, "It is always wise to charge."
 * The final battle in The Lion the Witch And The Wardrobe is this to a T, though there is some strategic use of boulder-dropping fliers before the forces clash.

Video Games

 * A trailer for Warcraft III shows this, with a battle between Orcs and Humans which quickly goes in a different direction when demons unexpectedly rain from the sky and kill everyone.
 * Happens in the intro to Warhammer 40 K: Dawn of War. Possibly a Justified Trope, as after the Blood Raven commander collapses from being shot and placing a flag at the top of a hill, Space Marine drop pods fall from the sky behind him. The flag is theorized to be some sort of device to call in those reinforcements from the drop pods, so the Blood Ravens had to make a reckless charge.
 * This is largely how infantry combat plays out in Black and White 2.

Real Life

 * In the Napoleonic Wars the British had a variation of this. They would wait. Occasionally chant. But mostly wait like a silent inhuman wall. This would push the soldiers tension to it's absolute limit which often came at the same time as the French were worn out. Then in a moment they would give a shout, fire their muskets, and charge. The French would almost inevitably collapse.
 * Less professional and/or poorly led armies often turn to this strategy. The typical result is a bloodbath if their enemy does the same, or a one sided massacre if he doesn't.
 * Of course, it makes slightly more sense when there's no cover to speak of and the other side has superior artillery support, but a sensible commander avoids getting into such a situation in the first place.
 * This is a surprisingly effective tactic when the best weapons around are pikes and your troops are more disciplined. The Swiss used it for centuries.
 * A modern version of this, done for fun, can be seen at quite a few metal festivals. Witness: The Wall of Death.