I know this has been asked before, but the list seems to be getting shorter every day.
Cryonics.
There are two cryonics providers in the entire world: Alcor and the Cryonics Institute. Neither of which accept Bitcoin as a means of payment despite the fact that both the transhumanist community and Bitcoin community are largely composed of libertarian computer nerds.
EDIT: It looks like I haven't been keeping up with the latest news! It seems Alcor just started accepting Bitcoin for cryonic suspensions since 12 days ago! Hah!
http://www.reddit.com/r/Bitcoin/comments/27yjsu/you_can_now_pay_for_your_own_cryonic_suspension/