An anniversary game would be a treat idea. How about setting a game around the first ever episode - literally. The centre of the board could be a small, fenced off junkyard, in sits the TARDIS, the First Doctor, Susan, Ian and Barbara.
Around the junkyard are some streets, in which the 11th doctor must defeat an enemy who is attempting to meddle with the doctor's timestream by killing or otherwise messing with Doc1, Susan, Ian and Babs (or somesuch).
Doc 11 has to do this without Doc 1 noticing... Well, you don't want spoilers now do you?