I've been doing a lot of searching and tinkering, and I'm having trouble figuring this one out. When I'm not using Wifi, my phone sleeps whenever the screen is off. When I'm connected to Wifi at my home, the phone almost never sleeps.

Facebook is set not to sync contacts (under Settings > Accounts and Sync)
The Facebook app is set not to issue notifications (couldn't find a sync option)
The battery history in Spare Parts isn't working. (Force closes)

Anyone have any ideas what might be keeping my phone awake? Or know of any apps or ways to see what's issuing the wakelocks? I'm stumped.