Earlier this year, in the midst of the free rigs that were being released to the Blender community, we got this clever little gem submitted to us by Ruben Lopez. It's a very simple lower-body rig, but the controls for it are quite nice and it's an excellent resource, especially for Spanish-speaking Blender users.
I've just ended the third version of my rigged legged sphere. It's a very simple model, inspired by the AnimationMentor one, that could be usefull for people learning animation with blender (like me). It's free with a Creative Commons By-SA 3.0 license. I've this setup hosted in a low-speed server, here: http://pinguino.dyndns.org/hospedados/bola_patas3.blend.zip
And the website explaining the steps for doing this setup and other things about learning animation, which is written in spanish, is this one: http://squash-stretch.blogspot.com
As I learn animation with the invaluable help of an animator professional, I keep posting in this blog all my achievements and even the theory that my "professor" gives to me. I write it in spanish with the hope of bringing together blender animation and the spanish community. Unfortunatelly there aren't too much resources in spanish on this topic.
Ruben's blog is completely in Spanish, but it's pretty easy to read if you translate it through Babelfish or Google. You can find the specific article about this rig in this post.