The new Bullet 2.81 Physics SDK is released. It includes an Apple contribution of SIMD and Neon optimizations for Mac OSX and iOS. Some new features include rolling friction ( so that curved shapes such as sphere, cylinders and cones will stop rolling, even on a sloped surface), a gear constraint, force and torque joint feedback, optional Coriolis forces and speculative contacts for fast moving objects. For more information and feedback see
http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=8490
Also Cebas released the 3ds Max plugin thinkingParticles 5 and it features Bullet Physics. Check it out here: http://www.cebas.com/index.php?pid=news_next&nid=489