I love Github. Love love love. What a great contribution they make to the world of collaborative software development.
I am an old dork who is used to using CVS, so I still forget a lot of git commands and am always looking them up. But not anymore. I downloaded a pretty git cheat sheet from Zack Rusin and have now set it as the background wallpaper on my secondary monitor for easy access. It looks pretty and it is totally functional. Pretty much a win / win.
Download the git cheat sheet at github: https://github.com/nerdgirl/git-cheatsheet-visual