I love seeing videos of weird glitches in games, especially if they're over-the-top like this one:
http://www.youtube.com/watch?v=AbIVUgW0t0o
So, do you guys have any other awesome glitches they'd like to share, in video form or just recounting a personal experience?
Here's another 2K9 glitch. This game is starting to look kind of bad...
http://www.youtube.com/watch?v=HN3cGmtm81g&feature=related

Thief: The Dark Project had some good ones. If you leaned and turned in a specific way so as to hook yourself on a door frame or something, then release the lean keys, you would sometimes snap back like a rubber band, fly across the room and impact on the opposite wall with enough force to kill yourself instantly.
Sometimes doors would mysteriously float off their hinges and disappear though a wall, never to be seen again.
Deus Ex: Grenade bouncing.

I haven't played any MLB 2K game in ages. I am a devout follower of two baseball games: High Heat Major League Baseball and the MLB: The Show games. Other than Madden, I buy these games each year like it's a new testament to the bible.
Anyway, I haven't played games to the point I look for glitches (or they look for me), so I can't really tell you from experience.

Leisure Suit Larry: Box Office Bust, a game that is awful to the core, has several glitches that show just how shoddily-made it is. You can see examples of this in just about every review and video of it out right now, from Giant Bomb's Quick Look to GameTrailer's review. One of the funniest ones is shown in this YouTube video, where you can splutter around like you're a car. What's even more alarming is how easy it is to get these glitches to happen, as relayed in the video's description.

That was hilarious lol! "He does a barrel roll of his own!"

Half Life 2 Episode Two
http://www.youtube.com/watch?v=RXdqAJHLIa0
Stalker Clear Sky
http://www.youtube.com/watch?v=p0z1Pa1O8vY&feature=channel_page
I made these two videos. :P And I know EP 2 video is bad. :D

The amount of solid floors I've fallen through, into oblivion, it isn't even funny...
I particularly like the one in Playstation Home where you can transport yourself out of your apartment using a sofa and go and read the plaque that reads "you shouldn't be able to read this", as well as finding the hidden WarHawk mine.

In the first F.E.A.R. the first proxy mine i threw in each level would start to spin faster and faster the gradually levetate off the ground. an enemy soldier stopped to look at it once, tracking its progress towards the ceiling with his gun. it finally hit the ceiling dropped to the ground bounced up again and exploded in both mine and the soldiers face. That made me very nearly piss myself laughing.

Deus Ex, Paul's apartment. I had a bunch of flares in my inventory that I didn't want, so I went into my bags and dropped them all in rapid succession - click click click click click. When I got back into the game, they were stacked up four feet high, completely motionless, like a Jenga tower.
Flares
In Thief 2, I blackjacked a guard and threw him into a corner (guards don't wake up after you blackjack them). I left the room and came back later, and nearly jumped out of my skin when I saw what looked like a guard sitting cross-legged in the corner, staring right at me. After a moment I realized that he couldn't see me and wasn't moving, so I cautiously went to investigate. Here's what I saw:
Thief guard
As it turned out, the guard was still unconscious - he had just reverted to a standing position for some reason, though he wasn't animated at all. I could pick him up and throw him around, and he just stood there stiff as a board, but his legs always clipped through the floor. Then I tried throwing him onto the table...
Thief guard on the table

As far as glitchy/weird gameplay stuff goes, its hard to ignore the original Driver
http://www.youtube.com/watch?v=NecNaVZLrwc
I've never been sure if this was an intentional thing to make it funny and infuriating or if they just messed up a decimal point somewhere in their physics calculations. The survival mode had some spectacular crashes because of it though

Oh, boy, do I remember that game! If I ever become a professional director, I am making a movie where cars react like this. Reviewers can scold it all they want, but the majority of society will deem it awesome because it is cars flying off walls like it's a motherf**king bounce house. Remember the days when you were a little kid playing with your Hot Wheels but never actually bothered to build a track for them, instead driving them up and down the walls and furniture, creating bizzare situations with your brother where he would ram you into a bookcase, only to have you bounce right back and smash him into a door, where he would do the same and come flying towards you again, repeating in a neverending cycle until one of you got a hankering for some Kool-Aid, smacked the other's car down and barreled into the kitchen?
Either I had one strange childhood or that's nostalgia gold for a movie.

This game seems to employ The Three Stooges as their outfield. Seriously, I own 2K8, and nothing like this ever happened, but with three + videos out there, it's becoming very clear that this is one broken game.

Saints Row: The Musical
http://www.youtube.com/watch?v=9l_YN-yRCVY

I'm definitely going to buy that game now!

It wasn't just you :P Me & my brothers did exactly that, with proper verbal sound effects.
Never seen either of those. Made of pure win.