Sylvester's problem is cool.
Surprisingly, the rules of go are somewhat controversial.
This game is rather interesting. I figured out at least one position in which O has a simple forced win. A more interesting question is whether there are any positions in which X has a forced win. I doubt it.
I tried out my original rules Bohemia on a 4x4 board. It's a close game, but the first player can always win. I didn't try any possibilities where the bohemian moves first and doesn't pass. Here is an interesting question - If we take a generalizations of this game, in which there are sets of subsets which the square wins if any of them become monochromatic, and the bohemian can pass, and the bohemian can go first, is there any such game in which the bohemian can always win, but loses by passing on the first move? Note that my new rules aren't of this form.