I currently have a really good MySQL cheat sheet which comes in handy for all the extra details I don't deal with on a daily basis.
What cheat sheets are other people using?
I'm interested in vi/Vim, regular expressions, Linux, Python, etc. as that's where I tend to have the basic day-to-day knowledge but then keep forgetting more complicated commands or options which I don't use often. However, please feel free to post links to any good cheat sheets you may use as I'm sure others will find them useful.