I saw a special on TV about Parkour  - crazy street running and jumping. Are there any video games that let me do this?
Mirrors Edge  for the PC, PS3 and Xbox 360 heavily features parkour.
Assassins Creed  (also for PC, PS3 and Xbox 360) lets you do parkour as well. http://en.wikipedia.org/wiki/Mirrors_Edge
inFamous  - The main character is inspired by Parkour. http://www.infamousthegame.com/
Prototype  (which can easily be considered a rival game to inFamous) made a rather big deal of emphasizing the fact that you get to do parkour. Personally, when you can fly around and run up the side of buildings, I am not entirely sure it counts as parkour. http://en.wikipedia.org/wiki/Prototype_%28video_game%29
Mirrors Edge - First Person Parkour based game. PS3, PC, Xbox360
Prototype - Third Person Adventure game. PS3, PC, Xbox360
Infamous - Third Person Adventure game. PS3
Free running for PSP - Can be bought on PSP store, i know nothing else about it. PSP,PS2
Assassins creed I and II - Third Person Adventure game. Xbox360, PC, PS3
Uncharted - Third Person Adventure series. PS3
Prince of Persia - Third Person adventure series. PS3, PC, Xbox360
Those are the good ones, Im sure there are tonnes more. As a side note I would take a look at Brink, its not out yet but it looks promising, very fluid parkour movements and good gunplay.
If you are looking for a straightforward Parkour experience nothing beats Mirrors edge (Although personally I found the game frustrating and abit repetitive). Brink seems to combine Shooting and Parkour very well from the videos ive seen but I think its scheduled for later this year.
Prince of Persia Sands of Time is an older game that includes some parkour. I think the latest in the series may do as well, but I've never played them.
I know it's been already mentioned here, but I just want to stress that in my opinion, Mirror's Edge is on another league compared to games like Prince of Persia or Assassin's Creed.
It's not necessarily better than other games, but
All really give it a "more realistic" sense of parkour, and if you got curious based on a real-life demonstration, it will probably be the best choice for you.
There's a game called Free Running from some years ago, it's a parkour simulator and it plays like a skateboard game. I think it was released on PSP and PS2.