Here is a pack of 12 rigs, designed to be used for honing in those body mechanics and acting skills.
Check them out at: artofjoe.blogspot.com/p/blog-page.html
These rigs are for educational and non-commercial character animation use. They are not a rigging tool. If you want a robust and fast character setup tool, I recommend checking out Rapid Rig Advanced: creativecrash.com/maya/script/-rapid-rig-advanced-auto-rig-for-maya