I recently wanted to use a Animated Flash based Tag Cloud on my Blog site.
Then I came across with a plugin from Joseph Chang (octopress-cumulus), but unfortunately it generated only category clouds.
So I updated the plugin to create a flash based animated cloud for tags also.
Note: you will have to use any other plugin to generate the tags first.
Here is the plugin code:
You can also find the updated plugin here.
Github - TheAshwanik/octopress-cumulus
or here Github - bizkit/octopress-cumulus