My spotlight recently got hosed, this is a good reference on how to fix that.

I had this problem turn up the other day. Rather annoying, but a simple Terminal command will take care of it. "sudo chflags hidden /private" (the /private is the folder you want hidden).

A $15 OS X app that takes a screenshot of your current desktop. The catch? The screenshot is saved as a PSD with layers for each application, window and desktop icon. (via shauninman)

Create a script that will have a custom song play from iTunes when mail from certain users arrive.

Resetting Mac OS X Passwords