BOTS

http://bots.acclaim.com/

BOTS is a free to play multiplayer online robot fighting game from Acclaim Games. Choose from three different BOT types, each with special abilities and unique attributes. Upgrade your BOT with customizable parts and weapons. Features three types of gameplay: Sector, Player vs. Player, and Base vs. Base mode.
Battle evil robots in Cyberspace! Customize your robot with tons of parts and weapons.