Back when I was at school, I remember tinkering with a Mac game where you programmed little robots in a sort of pseudo-assembler language which could then battle each other. They could move themselves around the arena, look for opponents in different directions, and fire some sort of weapon. Pretty basic stuff, but I remember it quite fondly, even if I can't remember the name.
Are there any good modern day equivalents?
While it was more logic than programming per se, one I really enjoyed back in elementary school was Rocky's Boots. It had sensors, AND gates, OR gates, NOT gates, wires, timers, and all sorts of other stuff. Fantastic program for teaching a kid logic.
Go to the link and you can still play it!
I got myself addicted to uplink a few months ago. It's not really coding based, more hacking. It's still fun and super geeky.
I'm surprised that Space Chem isn't mentioned yet. Programming with symbols, but programming nevertheless.
http://spacechemthegame.com/
I think .NET Terrarium is one of the best 'learn-to-program' games for the .NET platform.
Matt, I think the game you're referring to is CRobots (or one of its clones, perhaps -- my first contact was with PRobots, in Pascal, if I remember correctly). It was a lot of fun.
Although not strictly programming-based, I enjoyed a lot Robot Odyssey, a game where you wired logic gates to sensors and motors in a robot, to make it move and react to environment, to get out of a city, escaping obstacles. I played in on Apple //e, it was one of the best games on this computer (with Lode Runner! :-)).