No I am not talking about the feelings or biological chemicals this time.. In this case it is the company NaturalMotion and their software Euphoria and Endorphin! 
I remember watching the tech demo for Endorphin a while ago and thinking, WOW, this is some awesome shizz! Since that time Rockstar games has implemented the video game version of the tech called Euphoria into a few of their games to great success. Endorphin is designed for animating with 3D applications, and who knows how many movies have used it as well.
What does it do? This software blends the ultimate combo in AI controlling animation through behaviors. Think of it as a sort of realistic physics based parametric animation system for characters that is controlled by an easy to configure artificial intelligence!
If your an animator and you haven’t heard of this before it is really awesome and although it might be a bit pricey it could save you a ton of time for certain things, go ahead and check it out!
There is a learning edition of Endorphin where you can mess around and use the software to punch some dummies with variable forces. : )
http://www.naturalmotion.com/products/endorphin-le/
