From Amazingmoms.com:
A Special Welcome
Enlist or hire some high school or college theatre students to provide theater makeovers as the guests arrive.
The rest of the party can be less structured. A showing of the movie, singing Karaoke, a dance lesson, or encourage the partygoers to create their own choreography to perform on stage.
Tip: Keep in mind that not all children love to perform whether it's singing
or dancing. Be sure that those guests can use another gift like running the music, lights, make-up, or cheering for their favorite performers with pom-poms that you provide.
Wildcats Pennants
As an additional activity provide the supplies for making a Wildcats pennant to take home. this will be made using red and white craft foam and a craft glue stick. The kids can cut stars and letters, or provide pre-cut letters and shapes that you'll find at most craft stores.
Birthday Party Treats
Serve traditional theatre fare, such as popcorn, soda, large boxes of candy and hotdogs.
High School Musical Birthday Party Games
If you feel the need for an extra activity try these party games.
Search for the Cell Phones
Mrs. Darbus has hidden everyone's cell phones. The kids have to find them! Before the party hide several plastic, candy filled or lip gloss cell phones. Write clues using the movie as hints. You'll find a fun quiz and
other ideas that may help on the High School Musical Website.
When it's time to play, the kids will work as a team to answer all
of the clues and find the cell phones. Of course everyone gets a
phone to take home!
Name That Tune
Have the children take turns humming the first few notes of a High School Musical song. Can the other players guess which song it is?
Keep adding notes, or even words as additional clues when necessary.
This game can also be played with other popular songs.
Who Said It
Before the party, write down several lines from the movie with the character that said it, on slips of paper. The players take turns selecting
a slip of paper form a basket. Then, they'll say the quote aloud and see who can guess the character from the movie that belongs to that quote.