People in TF2 I encountered today didn't really know about Linux all that much (the fact it has different distros, different desktops, different ways of installing it, etc)...
I'd like to encourage people to make videos explaining all these facts. If you can, explain it to them like they are 12 or younger (because many of them are, granted their parents gave Valve permission, as per American law :P) that would be nice.
You can also choose to only explain Ubuntu+Unity (and maybe Wubi), since most people use that anyway and find it easy to use and install. Or you can explain how to install your own setup. People will be searching for different things.
Stick it on Youtube, stick it on Steam, explain in major foreign languages (Portuguese/French/German/Chinese/Russian/Korean) if you are better at it than English, so that we get as much coverage as possible. Remember to imagine yourself in their shoes.
I'll do one myself later on when I have time.
Doing this will increase the size of the Linux community on Steam, and thus increase the market Linux has, which will prompt publishers to think of us more. So we get more games! :D
PS: If you don't want to make a video, maybe make a guide: http://steamcommunity.com/app/221410/guides/