Run Linux on your iPhone, iPad, or Mac from a Web Browser
If you’re bored of the Mac command line this is both cool and geeky and should keep you entertained for a bit. JSLinux is a fully functioning version of Linux running entirely in a web browser, meaning if you have almost any modern web browser suddenly you can run a basic version of linux on any computer.
A friend of mine claims this even works on the iPhone and iPad and I don’t see much reason why it shouldn’t. Unfortunately I tried running this on my neolithic iPhone 3G and Mobile Safari had trouble rendering JSLinux (screen below), sometimes it even crashed, but YMMV and this could be a problem with the stone age 3G and iOS 4.2.1 more than JSLinux itself.