For those of you who have not seen how pretty the Mac OS X GUI really is, I pity you. :P Anyway, one of the hacks available on the Mac is Growl, a notification system. Applications using Growl can provide non-obtrusive ways to notify users of the status of the application. The image here (taken from Adium) shows an incoming IM message. Wouldn't you think this will be cool to do on Linux?

Well, don't worry! IBM's Nathan Harrington has a tutorial on how you can achieve something similar. Similar but not quite since it still needs a few more gooey polishing. :) So there, hack your Linux and see how pretty it can go. :)