http://www.newscientist.com/article/dn17...-good.html

Not saying there's a connection really, but it's kind of interesting that how when I taught myself to juggle was right around when I started to feel myself doing well in Japanese. Still seems far-fetched, though...

Interesting article, thanks for sharing

I have also read that senior citizens who take on trying to learn a new language have a much reduced occurrence of Alzheimer’s.

combine that with

http://www.newscientist.com/article/dn89...atter.html

note that "Golestani stresses the results only deal with a person's ability to understand foreign language sounds and do not relate to other aspects of language, such as grammar."

I can juggle with 5 balls at a time, and some years I was close to 7. So why does it take me so long to gulp down RTK1? :-)
Really, juggling or not, I think the point is learning things unusual to you. It could be just wrestling as well, which implies you to move your body along the "6 spatial degrees of freedom" while external forces (gravity, your opponent, your biomechanical limits...) exert constraints on you.