Are there any FOSS / open source e-sports games you're excited about?

It occurred to me that I don't know any FOSS e-sport games off the top of my head and I don't know why. I looked it up and it doesn't seem like there are many tournaments around and I got to thinking about what would make a good FOSS e-sport and I don't know that I have a really clear idea of it. It's been on my mind a lot though so I wanted to see what you all think about it.

What FOSS e-sports do you like? What do you wish existed that doesn't? Do you think there should be FOSS e-sports? Do you think they'll never work, never be sustainable, or not be good? Does the concept of monetized tournaments go against the very ethos of free software?