Lets see... I can crack my toes, ankles, knees, hips, back, neck, shoulder, elbow, wrist, and fingers... I've even cracked my jaw once. I'm not so sure it's a good thing, but it's certainly helped me maintain youthful flexibility thus far.
I also dive into accents, impressions and characters without warning or provocation. Once I went a whole hour in an Australian accent. Someone finally tricked me into breaking it
Hm. I can walk on my knees with my legs crossed in the "lotus position". You know, the one where your feet are on top of your legs.
That's about as weird as I am.