There are a number of games I run frequently that I really wish someone else would run, for once, so I could play in them. My standard PHB/OA/SJ D&D game, Street Fighter: the Storytelling Game, any of the settings I'm trying to develop for publication. Marvel Heroic Roleplayin, especially in the eXiles format I initially popularized.

But I see running a game as... a kind of a performance, a kind of a service, and there's nothing I love more than combining "making people happy" with showing off.