Fun little puzzle game: Color infection 2
 

Thanks to Not_Right_Now who posted the Torture game. That website lead me to Color infection which is a fun little game where you try to "...infect all yellow shapes with brown color by colliding them with brown shapes but keep all green shapes uninfected."

Color Infection 2 - KeepBusy.net

What I really like about the game though is that it has an editor that lets you create your own levels. That can be found here: Color Infection Editor It's a semi-complex editor and takes a little bit of time to figure out everything but once you do it's fairly easy to create some puzzles.