Architectural Engineer: Pretty good knowledge of where windows, stairs and such are going to be and how to find them whether in dungeons or elsewhere. It also sorta carries over to the PCs I play by having them 'know' how a building is supported and layed out. Mostly though it deals more with game geometry with buildings around, such as hiding under the gables of a roof, or knowing which angle may be the best for a crossfire ambush.
Tour Guide Volunteer: This helped a lot with public speaking and how to communicate effectively (and possibly loudly) to players as a DM. It's kept me from ever stalling in an adventure yet, as well as add more drama to combat and effects. I think it will help with the outgoing bard I am about to play soon too.
Drummer: I like to surprise my players once in a while with a confrontation of an insideous villan that acts sinister by flipping and twirling pencils, rulers, maps, whatever. I got some feed back that they loved it as a prop addition to the hatred they had for him. Can't do it all the time, though, gotta lay off til they least expect it....