Don't think everything you do has to be funny...
All you need to do to be interesting is be specific, and if you need to be quiet for a while, that's fine...
Jokes and bits in an improv show are a defense mechanism for people that don't know what they're doing.
Work on developing your basic improvisation skills first. Once those are in place, it's very easy to layer the gimmick of a game on top of them.