Ah, sweet, sweet Robo-Rally. If there is a Valhalla for board games, truly, you hold a place of honor within its halls. This was a board game designed by Richard Garfield, of "Magic: The Gathering" fame, and is justly remembered by board game fans all over the world as a brilliant piece of game design, a tremendously fun game to play among friends, and a challenging game with simple rules. That's pretty much the trifecta of great games, right there.
In the game, you play a computer who is controlling a robot remotely, sending it through a factory floor that has been converted into an improvised race-course (while not shutting off the conveyor belts, crushers, welding lasers, and other sundry obstacles. After all, it's a factory that builds robots. Plenty more where that came from.) You send commands to your robot by playing cards, which it interprets as instructions to move forward, back up, turn left, turn right, and so on. Pretty simple, right?
Yeah. Except for three things. One, the aforementioned obstacles. By the time all the expansions were released for the game, these included flamethrowers, toxic waste, oil slicks, bottomless pits, teleporters, and flooding. Everything did something to your robot, and pretty much none of it was good. (Well, the teleporters could be good. And if your robot fell into the toxic waste, it could spontaneously develop super-powers...)
Two, everyone took their turns at once. You lay down five face-down cards, representing your "program" for that turn, and everyone flipped theirs over at the same time. Another robot gives you a hearty shove, moving you three squares to the right of where you thought you were? Your robot just kept right on executing the program you told it to, even if that sent it into a bottomless pit. Made a mistake laying down your cards? Hope you survive to correct it next turn. The gleeful chaos of one turn of Robo-Rally put some entire games to shame.
And three, your robot wasn't just limited to two states, "fine" or "dead". Lasers, flamethrowers, and the like could damage your robot, reducing the size of your hand of cards and giving you fewer options in programming your robot. With a small enough hand size, you would actually have to leave your cards from last turn in play as your robot's antenna broke and it kept repeating the same actions over and over again.
All this made the game brutally fun. (It worked even better with an "unlimited lives" house rule, which allowed you to be a bit more cavalier about the many many times robots went boom.) The game won four Origins awards, released four expansions, and was re-released in 2005, but is sadly now out of print. (There is an online version at GameTableOnline.com, which includes a board editor and is hence automatically the Coolest Thing In the Whole Wide World Ever, but I've never been able to get the damned thing to work on any computer I've ever tried it on.)
So if you can track down a copy (try eBay, or a gaming store that stocks used games), this is a once-in-a-lifetime good game. Get seven friends together, pick out your 'bots, and go nuts. You won't regret it.