Here are a few plugins I have done.
he Official Bacon Ipsum Plugin as seen on
http://baconipsum.com
Automatic Adult Video Embeds
HTML5 Audio Player
AppStore Poster (itunes,etc)
MLB.COM Content Importer
Secure Encrypted Expiring Downloads for member content
Zip Gallery (generate a zip of your gallery for download via ajax backend)
MSN IM Plugin
Popunder Plugin
VideoBash Content Importer