Here's the general answer, based on WB's current guidelines for one-time uses of the HARRY POTTERŪ trade mark and other protected materials for small scale local events (including stage plays and musicals) of a non-commercial, not-for-profit, non-profit and non-political nature. It's designed to allow things like the local chapter of a "registered" charity, an accredited learning centre, a "recognized" religious organization, a school, a public library, a local civic group or the local chapter of a "recognized" kids' organization to put on small-scale HP themed projects. If you want to do more, you need to get in touch with Amber Fredman at WB, but they're not giving stage rights on a larger scale than this right now - I know, as I asked about it in July.

Their rules are:
- If your event is designed to raise funds, your group must be a small local charity, the local chapter of a "registered" charity, an accredited learning centre, a "recognized" religious organization, a school, a public library, a local civic group, the local chapter of a "recognized" kids' organization. (It is possible that other similar, local organizations may qualify. Please contact us for clarification.) 100% of the funds raised from your proposed activities must go directly to the relevant qualifying organization involved.

- Admission donations should be appropriate for a small, local, non-commercial event, e.g., no more than $5 per person for adults and $3 for children under 12.

- No supplier to this HARRY POTTERŪ themed event may make a profit in association with the goods or services that it is providing to this event. Caterers, builders, printers, etc. should donate all sums to the relevant charity.

There's some other quirks on advertising locally only, etc. so let me know if their plans meet the above criteria and pass them on, too. Btw, as I understand it, one time only can mean multiple performances in a limited period of time.