The Growl Project has released Growl 2.1, adding the capability to run scripts as actions as well as control notifications via rules using AppleScript. (For more information on writing AppleScript for notifications, see this documentation page.) The system-wide notification utility also addresses a problem with hanging when receiving more than 100 notes at a time, enables use of styled close buttons on WebKit displays, localizes Automator actions, and displays notes on both computers when using forwarding with Notification Center forwarding. ($3.99 new from the Mac App Store, 6.8 MB)
Disable Caps Lock
If you find yourself pressing the Caps Lock key accidentally as much as I do, note that you can disable it entirely in Mac OS X. Open the Keyboard & Mouse preference pane, click the Modifier Keys button, and in the dialog that appears, select No Action from the Caps Lock pop-up menu. You could remap it to another modifier instead, but that might make using differently configured Macs more difficult.