One of the things I like to do on occasion is pop on some music I don't usually listen to (dubstep) and do some free form to unfamiliar songs.

May be odd, but I feel that for me personally it has training value because it helps me stay loose and not get to rigid or locked into a certain way of thinking. Helps me not take myself too seriously which I think as a martial artist in any capacity is pretty important. Also your opponent's will always do something unexpected, so if you learn to keep pace with unfamiliar rhythms it helps you not plan too far ahead. Anywho here's me being ridiculous.