Noodlesoft released Hazel 3.0.14 to enable you to edit notification options from the file cleanup utility when running in OS X 10.8 Mountain Lion. Accessed via the gear pull-down, you can select Notification Center or Growl (if you have the latter installed) and specify which kinds of notifications should be displayed. (By default, Notification Center gets the nod if both are available.) The update also fixes instances of Hazel not keeping track of Trash if it is empty on startup and more reliably matches patterns with accented characters. Noodlesoft subsequently issued version 3.0.15 to fix a crash in notification options and a disabling of the gear pull-down when notification options are available but no folders are present. ($25 new, free update, 6.2 MB, release notes)
Option-click to Hide Apps Quickly
This trick has been available in the Mac OS for years, but many people still don't know it. If you have too many windows cluttering up your screen, you can hide specific ones easily as you work. When you're in any application, hold down the Option key and click on another app's window, on the Dock, or in the Finder to switch to that other app and simultaneously hide all the windows in the previously current app.