High School Musical 4

I think that four is one to many but this is from TV Guide:

This fall's big-screen debut of High School Musical 3 may not be the most anticipated chapter in the franchise anymore. Of course, that's only because there is already the promise of a High School Musical 4.

Disney Channel Worldwide president Rich Ross on Tuesday confirmed that a script is currently being drafted, adding that — at least for now — the newest film would be a TV-movie rather than a theatrical release. Although casting at this point is still up in the air, Ross hopes to retain some of the original ensemble, which is currently gearing up to shoot HSM 3 in Utah.

They have definitely jumped the shark...

Don't count on Ashley Tisdale returning.

No 'HSM4' For Tisdale?: The announcement that Disney is already planning a fourth installment of the "High School Musical" series has fans wondering if Troy, Gabriella, and Sharpay will be back for more singing and dancing. But don't count in Ashley Tisdale just yet. The actress told Us Weekly, "It will always be a part of us that we loved to do. All of us have gone through so much together, like winning the Billboard Award and an Emmy and an American Music Award! That's something that we'll always remember!" So what's next for her? "I'd love to do more romantic comedies in the future.," she added, calling Kate Hudson an inspiration. A "HSM" without Sharpay is not something we're going to be able to handle.