I don't think I have any characters who would be involved in the club (though Evie could probably be coerced into working tech, assuming it involves pretty charmwork), but I do have an interest in theatre IRL, so I can't help but get enthusiastic for my own sake – haha!
As far as Potterverse plays...
According to the commentary after The Fountain of Fair Fortune in Tales of Beetle the Bard, a dramatic adaptation of the story has been presented at Hogwarts in the past. As far as technical effects and cool scenery, Rowling writes that there was “a fully functioning Fountain of Fair Fortune and a miniature grassy hill, up which our three heroines and hero would appear to march while it sank slowly into the stage and out of sight.” The role of the worm in the play was even played by an engorged ashwinder which, in hindsight, probably wasn't a great choice. There are three strong female leads and a single male lead, which isn't a huge cast, but I think there is room for either doubling, swinging, or understudying, which could be fun IC-ly for the characters involved in the production. There also may or may not be pressure to call the whole thing off, since the story involves a major romance between a witch and a muggle which, in some circles, may be considered to be in bad taste.
It could easily be performed as a straight play, but in case you haven't heard of it, there is also a short Wrock Opera called 'Fair Fortune' based on the story, written by Lena Gabrielle (Of 'The Butterbeer Experience' and best friend of Lauren Fairweather-Maggiacomo of 'The Moaning Myrtles' fame, if you're into the old school muggle wizard wrock scene). It's about 20 minutes in length, so if you wanted to sort of “borrow” it as an in-character musical, you might have to either use it as the basis and pretend the actual show is longer, or use it as part of a longer short play/musical festival of sorts.
Thanks to the magic of youtube and the internet, you can watch the whole thing right now!
Here is
the first ever performance from earlier in 2009, which has the entire thing all in one video.
And here is
part one of the show, performed again, this time at Azkatraz in Summer '09, and here is
part two.
And if neither of those are quite clear enough for you, you can listen to the soundtrack to the whole thing (with all dialogue included)
here, on bandcamp and you do not have to pay for anything unless you download it.
Roles in this version of the show include:
-Amata (great part for an ingenue type)
-Asha (great part for someone dramatic and ridiculous -plenty of writhing in agony)
-Altheda (great part for an all around strong performer)
-Sir Luckless (excellent comedic part)
-Narrator (which can technically be split many ways and become 3-5 roles for males or females, if necessary)
-The worm (probably wouldn't want to use an ashwinder again – might be a fun part for two students to play...)
There could also be a chorus/ensemble added, if you were interested in depicting the many, many hopeful individuals who traveled to the garden in pursuit of a dip in the fountain. There's no number like that in the version I linked to, but there's no reason why we can't add one!
So that's potentially as many as 11 named parts... if you doubled the leads it could be as many as 15, plus ensemble. So, in theory, this production could accommodate a cast of 20-30, assuming the ensemble doesn't mind appearing in like... one number, and potentially a finale.