Today is Twitter Cartoon Day 2 – or, for brevity’s sake: Twoonday.

The idea is simple: cheer up the Twittersphere by changing your avatar (picture) to a cartoon character.

Last year was fun, but this year there are more of us on Twitter, and more things we can do.

There’s a Flickr group where you can submit your screengrabs, and @AlexGamela is creating a Google Map of Twooning Twitterers. I’ll also be creating a tagcloud of the words most used with the #twoonday tag (thanks to @psychemedia for help with that).

The image above is designed to fit neatly on Twitter wallpaper. A larger version is available on Flickr.

Tag your tweets #twoonday to join the fun. Follow the tag here.

After all, it’s Friday!