What is a good RPG to play for about 10 sessions?
As someone who has switched from multi-year campaigns to a dedicated limited-series model (all games limited to 6-8 episodes, quick turnover, many choices), I can't actually recommend anything for 10 sessions -- that's outside my experience and outside my wheelhouse. That said, I have a pretty good feeling that anything around Apocalypse World, Cortex, Monsterhearts, or Fate would work GREAT for a "mid-season replacement show" sort of game. Enough time for growth, but not enough time to become gods; careful management of time and resources without the "let's spend a session at the table shopping at the magic bazaar" problem of longer, more complicated games.
I can also tell you what systems probably don't work well for a 10-session cap: any flavour of D&D, GURPS, Hero System, Mutants and Masterminds... these systems are all, to my mind, "long-haul" systems -- games you sink a lot of up-front work into, so you want to play them for a while to get the value out of learning the system.
Your mileage may vary, of course; what do you think?