I have wrapped a TUAW script to check for Mountain Lion into an Alfred extension here. It just tells you whether Mountain Lion is available yet.
The most popular extension on this site is Time Somewhere which was helped greatly by @jdfwarrior‘s WolframAlpha extension. He also made Extension Updater which my shell script extensions now support (everything but Relaunch, Consider Unpausing and Windows Booter). Just install the Extension Updater extension and type update check to check for updates or update to check for and install updates. Check out his Tumblr for more great extensions.
Download Consider Unpausing for Alfred Powerpack. Basically I often pause iTunes to, for example, watch a quick clip on YouTube and then I forget to unpause and spend the next hour in silence. Now I just type cons into Alfred and after 5 minutes I get this notification:
You can also specify a number of minutes until you are reminded. If you don’t enter anything then 5 minutes will be used.
Download Snap for Alfred Powerpack extension to take a picture using your iSight / FaceTime camera. Just type snap into Alfred and you’ll have your picture taken and saved tp the desktop in the same format as screenshots are – Something like “Snap 2011-11-23 at 00.43.51.png”.