Oblivion - Easy Level Up

This trick requires you have Conjuration as one of your main skills, and works best if you also have a weapon skill (i.e. blade, blunt) and destruction.

You'll need a summon spell ( I use skeleton because you can get it early in the game) and a weapon or destruction spell. Summon a skeleton and kill him using the weapon or spell that will effect your major skills and repeat this process. If you have block as a major skill you can train 3 skills at once, and if you combine sword fighting with magical attacks, you can even train 4 at a time.

GTA IV - Riot

Make several taxi drivers mad at you (hit there cars or steal them) and then get one of them to hit the other (just walk behind one person while the other is swinging at you) and you can quickly get several of them fighting amongst themselves.

GTA IV - dumpster glitch

In WestMinster, there are two dumpsters against a wall near the water, if you climb onto one and try to jump from it the ledge on the wall right above them, the dumpster will flip over and move like something hit it.

GTA IV - Glitch at hospital

Go to the hospital in NorthHolland, drive a SUV or other large car up to the red shelter at the front door. Climb onto the car, and jump from the car to the shelter. Walk to the back of the shelter and down onto the ledge on the wall where the hospital cymbal is, and then climb back up onto the red shelter, Niko will start to fall through the shelter and then jump several times before standing still.

Crackdown - Drop cop cars

If you pick up a cop car and jump into the air and drop it, it will fly a little ways and land on the ground. Although this will sometimes kill the cops in the car, they won't attack you.

Dead Rising - Escaping crowds of zombies

Once unlocked, you can use the jump kick to knock several zombies out of your way.

Dead Rising - Katana and Battle Axe

In the upstairs part of the entrance plaza, there is a store that has both katanas and battle axes. This is the closest store to the security room that has these weapons.

Crackdown - Cars go crazy

Sometimes if you shoot all the tires off of a car, it will start sliding around out of control.

Dead Rising - Using the sledgehammer

If you get a sledgehammer (from the warehouse or from a hardware store) you may not realize it has two attacks. The first attack is a slamming the hammer down towards an enemy, sometimes beheading them which works great for a single opponent, but you can also hold x down to swing the hammer around, hitting several enemies at once with less damage.

Turok - Using the knife

If you think the knife is useless against heavily armed enemies, think again. It's possible to clear out an entire room of human enemies with just the knife, and even easier against dinosaurs.