I don't think I need much external stimuli to keep me entertained, honestly. If I'm for example in a tricky spot where I'm in danger of becoming bored I'll just start amusing myself inside my head, actually boredom is something I have hardly ever experienced.
I can't imagine anything worse than boredom, though!
When I'm alone, I usually want to keep myself preoccupied with something. Writing is a really helpful tool for me to arrange my thoughts, feelings and stuff. I pretty much enjoy coming up to new understandings, and I can use any means to get to them really. Watch something (a movie, tv show, documentary etc), read (books, internet). Going for a walk. I also just love feeding my imagination, and any means work for that as well.
I keep the amusement part inside my head mostly, most people have no idea about the absurdities in my head. I love the twisted version of reality that's in there however, it amuses me greatly.