Flashteroids

Online Flash game based on the concept of the arcade classic Asteroids. Collect all the flashing targets that appear in sequence, in as little time as possible. Offers three difficulty levels.
http://www.flashteroids.com/

Mediaroids

Try to get the most points possible in this online Java game based on the original Asteroids arcade classic.
http://www.medialore.com/games/mediaroids/mediaroids.html

Belter

Battle over 20 different kinds of space debris, grab power-ups, and solve puzzle stages in this action space adventure set outside the orbit of Mars, in the asteroid belt. Requires Flash.
http://www.truantduck.com/belter/belter.html