#RPGaDay day 21:
None.
There are some RPGs set in licences that I'd absolutely like to try (#thronering, FFG #StarWars and the #Warhammer/ #40k stuff, for example), but I haven't played any yet.
I'm also a little sceptical if it could really work well with so much predefined and probable big differences in prior knowledge between players (very different between the different licenses, of course).
Best variant is probably to just use the setting and stay far away from any VIPs.