These are a few games that utilize a 'physics' engine which mimics natural physical forces and makes for an entertaining way to burn some time.
Can you think of any popular games that mimic physics to portray a more realistic and fun game play?
How about Angry birds? Or any of the major first person shooter games, Battlefield, Crisis, and Modern Warfare.
The Gun game
http://www.bored.com/game/play/729/The_Gun_Game.html
Blosics 3
http://www.bored.com/game/play/151644/Blosics_3.html
Chick Cannon
http://www.aceshootinggames.com/shooting-games/chick-cannon.html