George R. R. Martin has been teasing fans a few years now with riddles like this one (warning: really elaborate spoiler for one very minor plot point). The actor half of the clue (it's role first, then actor. I don't want to get into it. It makes my head hurt) reads thusly: "He knew Indiana Jones, has hung with droids and jedi, thrice contended for a Larry, winning once. He's been a knight (often), an archbishop (twice), a dean, a priest, a doctor."
Consensus among the GRRM commentariat seems to be that this points to Oliver Ford Davies. From commenter Stefan Radermacher:
He was Sio Bibble in "Star Wars", he played a ship's captain in an episode of the "Young Indiana Jones Chronicles", he played archbishops in "Johnny English" and "Bertie and Elizabeth", her was the Dean of Windsor in "Mrs Brown", and he was Doctor Harris in "Sense and Sensibility". He also played various knighted characters on different movies or TV shows (like "Sir Richard Bowman" on Spooks, for example). Also, he won the Laurence Olivier Award in 1990, and was nominated in 2003 and 2007.
Most folks also think the role being riddled is that of Maester Cressen, a kind of court doctor character who first appears in the prologue to "A Clash of Kings" (which will be the subject of the second season of the HBO show).
If you are an IMDB whiz, check out grrm.livejournal.com whenever you get a yen to put your skills to the test; the clues are quite elaborate and you'll usually come back with some kind of not-yet-available info about the show.
Pic via the ever-dependable Meme Generator.