(Video Link)
YouTube user Frabjousfilms made an a cappella version of the Doctor Who theme. At least, that's the way it starts out. Then he works in signature lines like "Always bring a banana to a party" (the Tenth Doctor). Now lest you think that this video is too weird: it carries the endorsement of executive producer Steven Moffat.
-via Nerd Bastards
Previously: Every Version of the Doctor Who Theme, 1963-2010