EPT Kazoo is the font that I created for lettering Electric Puppet Theatre and is released under the SIL Open Font License.
If you'd like to hack on the font, download the source package and edit EptKazoo.sfd in FontForge. To edit the glyph shapes, you may find it easier to start by editing the individual glyph SVG files in Inkscape. If you'd like to contribute your changes to the next version of EptKazoo, please e-mail the modified files or patches to markv [at] eptcomic.com
Here is a list of other fonts that I use for lettering.