incredibots

One of the best physics games on the internet. Like phun, except it's updated regularly. New features that aren't in phun include triggers, which if one shape hits another it does something, allowing for the creation of complex computers, and thrusters, which are like rockets. IB also has a nice userbase and forum.

A: I was playing Incredibots the other day.
B: Dude that game is awesome!