A group in the US performed a reading of "Monstrous Regiment" (Stephen Briggs's script). They called for volunteers to join the cast in the Terry Pratchett Facebook group, and it was aired "live" on Youtube. I did ask if it would be available for later viewing, but they said no, because of the rights agreements with Briggs and the Pratchett Estate/script publishers (Methuen, I believe). Heck, they were lucky to be allowed to do an internet performance at all!
I would have loved to have seen it (or even taken part), but their "airing" time was the middle of the night in Australia, because they tried to time it to have US and UK audiences.