Bullet Software & Open Source.

Bullet Software:
http://bulletphysics.org/wordpress/
Multi threaded 3D
COCOTO surprise uses bullet on Wii.
Film 2012 uses bullet software for a lot of the rigid body special effects.
Zero Gear is the first game of 2010 using bullet physics for its physics and ogre 3D for graphics rendering.
Bullet physics library is one of the best physics libraries on market today.
Trials HD Xbox 360 uses bullet physics library to calculate their physics simulation and collision inside the game.

Open source software:
Is a computer software, it allows users to improve software. Designed for the public access. Standish Groups estimated that Open source software saves consumers $60 billion a year.
Free software movement was launched in 1983. Although names was changed in 1998.