The CirclePack java software
Wonderful circle packings are 2 clicks away!!
You can download the executable java file (a JavaARchive .jar) here . © Ken Stephenson.
Then you'll need some data to encode your circles, the scripts are here . Look for .xmd files, save them somewhere and feed them to the CirclePack software. The Menagerie script is a good cherry picking. Don't forget to TRY things, like moving around elements and monkey clicking everywhere.
Have fun!