Stack Applet, vanity for your SE rep.
I mailed George Edison (the author) with some tips and stuff, and next thing you know he’s got it up on Launchpad ready to go, so if you want to dive in and start filing and fixing bugs, feel free to hop in.
The team PPA isn’t ready yet, so use George’s PPA to install it:
The package name is “stackapplet”. Many thanks to Luke Farone for uploading this into Debian (it’ll make it’s way into Maverick as well!).