My friend and I used to spend our lunchtimes finding pictures on WorldCityPhotos and testing the other to see if they could identify the country. After that, we started guessing distances between world cities or predicting world weather. We're both insane (and competitive), and we did get pretty good at it. Any place in the world, any time of year, we'll only be a few degrees out. I'd be rubbish at it but I hated him beating me, so I put the effort in. :D
Man, that sounded so sarcastic when I read it back just now, but I assure you, It wasn't.
Dammit, that sentence did too! Oh well, if you think I'm being sarcastic just deal with it okay :P