Nude Tai Chi . . . well, I had high hopes that I'd just made that one up, but Mr. Shirley says it's definitely real. I don't want to know how he knows; let's just say I'm taking him at his word and leave it at that. Maybe he only saw the instructional videos.
I'm guessing the Firefly fans out there know that people juggle geese on some moons in the 'verse, but not on Earth as far as I know. Wash has seen it with his own eyes. "Every planet has it's own weird customs. About a year before we met, I spent six weeks on a moon where the principle form of recreation was juggling geese. My hand to God. "
Chessboxing is definitely real. Fighters alternate rounds of boxing with rounds of chess in an effort to test both intellectual and athletic dominance.