The Flight Tracker dashboard widget that comes with Mac OS X 10.4 (Tiger) seems to have a fairly major bug. However, this bug seems to be the result of something quite obscure to do with timezones, and it only seems to manifest itself in the UK during the summer.
X11 Colors list for Mac OS X
A friend of mine is a recent newbie Mac user, after finally succumbing to the shiny white lure of the MacBook. As an expert Unix user, he was missing the old X11 colours list, because he can't have his terminal set up with a horrible shade of puce without having to work out the RGB values for it.