Phun

[ciphergoth]

Possible new best thing ever - although as previously stated if you don't already read bad_science then you are crazy.

Comments

[meico.livejournal.com]

Check out Crayon Physics too! :)

It is very pretty and it has proper game mechanics in addition to the "draw stuff and watch physics happen" mechanic. Though I must admit that the simulator in Phun does more things and looks more (numerically) stable.