Thing-Fish has been performed live in London twice -- the first time, only an excerpt was performed, then in 2003, they performed the entire play (see also:
Thing-Fish: is it a Myth or a Pancake?).
Joe's Garage was also performed live, but as a rock concert (ala Pink Floyd's
Wall concerts) by a group called Sex Without Nails Bros. (see also:
Joe's Garage - Sex Without Nails Bros DVD !!!). As far as I know,
Civilization Phaze III has not been performed yet. If you're looking for information on how you can buy the stage rights to JG and CP3, contact Gail Zappa, and propose a business deal. Others on this forum have mentioned making JG into a movie. I, myself have suggested that JG be an entirely rotoscoped animated movie, because I think that style would work really well with the story.