Our typical filter question is: "are you happy to use PHP, C++, Mongo, Java?"
Not that we have those in our stack yet, but it quickly weeds out those that sneer at any or all of that list. Let them destroy someone else's startup with their wanky tech attitude.
We are more interested in problem solvers.
The best answer we had was from employee # 2 - "if it gets shit done, and we ship, sure, why not?".