My wife has no proprioception. Like, she can't do that thing where you close your eyes and touch the third toe on your left foot without having to think about where it is.

The afternoon she figured out that I could do this was really fun with me closing my eyes and her being amazed that I could just TOUCH MY NOSE without having to grope around for it.

I have a thing called dermotographia where basically my skin swells whenever you scratch it. I used to think this was normal and just draw things on my thighs and they would swell into pictures. It wasn't until I was like 11 that i realized that other peoples' skin didn't swell up like that when they got scratches. Still pretty cool though cuz its like a non-permaneant notepad on my body since the swelling goes away after about 15 minutes.

Hypermobility - apparently it freaks people out if you stand with your knees bending the wrong way.