I recently I started a spinoff from one of Microraptor's characters. I will do some more pages and update now and then, but I can't keep up a regular webcomic beside my maincomic TOBT. So there is plenty of room for guest pages. Might be SFW or NSFW (just renember it is meant to depict a children's show, NSFW would be rather in a metaplot), but they should stick to the basic concept (a children's science themed television show) and the original cast. I worked out a cast list, Microraptor added several characters to it, and if you like to do a guestpage (or several ones), I can send it to you. (Microraptor has a copy of it, too.)
The comic is here.