With the intention of changing something... I'd probably either go somewhere something awesome happened and I didn't have my camera, but instead I would have my camera with me. Like the danceoff between my drunk mom and some nerdy guy married to a porn star.... OR even better.... Go into the past and invent something that has already been invented and would make me lots of money.

If I went to the past just to relive it with no consequences, I really don't know what I would do. Probably something bad. Or maybe I'd just eat lots of junk food.