Well, this thread is a weird coincidence ...
Normally, the only two things that will keep me up all night is gaming or reading. Actually, if a book or a game doesn't keep me up past midnight thinking "just one more ", I won't recommend it to anyone.
I say normally, because last night I met a really smart, really hot, really fun chick, who had tons of tattoos (I love that), who immediately got all my jokes (no matter how geeky or obscure) and I ended up spending the entire evening out with her, instead of my boys (it was guys night and my boys are married but they weren't mad because they visibly saw the chemistry between us). When I got home, my thoughts kept turning to her and I simply could not sleep. I would find this less odd if I was younger, but I'm 34 and she has me feeling 16 again. It's also odd because, normally, I can literally sleep anywhere, at any time.