The idea (a very rough sketch) for this is to break the standard mold of silly logos on the Plone conference page.
Use a photo of the group sitting around the lion, working as a team to hold up the plone indicia.
Include a handlettered location and date sign. Everybody smiles! Everybody is a team! At Penn State! At the conference, stage next years photo with all willing participants. Add the plone logo and sign text with Photoshop.
Like an advertisement sprint...
...and if you really really need something for tee shirts, use this.