Physics is Phun!
Here’s another time-waster for all you folks! Phun is a "2D physics sandbox" that lets you quickly design all sorts of things and simulate how they will react in the real world.
Check out the video below:
Phun was created by Emil Ernerfeldt for a Master of Science Thesis at VRLab, Umeå University. "Phun is meant to be a playground where people can be creative. It can also be used as an educational tool to learn about physics concepts such as restitution and friction."
So go ahead, take a break and have some Phun!