Robowar is a freeware game ( formally shareware ) for the Apple Mac in which you program and pit robot gladiators against each other. There are small tournaments held monthly, with large ones taking place every six months or so. You can equip robots with an arsenal of weaponry and features, with the tournaments having various categories depending on the amount of hardware on your robot.

The robots are programmed in a language called Robotalk, a stack-based language which is similar to the language used on HP calculators. It's a very fun and enjoyable game for hackers, and is enjoyed by all ages.

An example of some Robotalk code is below -

Main:
50 shield' store
aim 10 + aim' store
range 0 > Shootsub if
main jump

Shootsub:
50 fire' store
return