go to the library, pick out a history textbook, anyone it doesn't matter, and find a comfy place to sit. skim (and I mean seriously skim--read captions for pics, section titles, and graphs/tables) for a few hours. take the CLEP test. win.
that's what I did for hist 105 when I needed to get some extra hours to get my Aggie ring early. it is THAT easy.