St. Louis has plenty going on during the summer months, but if it's good theatre you're after, consider these:
High Fidelity - New Line Theatre 5/31-6/23
Though it may have failed on Broadway, New Line Theatre (one of the best companies in town) demonstrated a couple of years ago that this is really an excellent musical. And, it was so good the first time around, they've decided to do a revival. I'm guess tickets will be selling like hotcakes for this production.
Ain't Misbehavin' - Stages St. Louis 6/1-7/1
Stages consistently produces quality musical entertainment, and this promises to be an evening of fine Fats Waller tunes.
Thoroughly Modern Millie - The Muny 6/18-6/24
The Muny opens with this musical based on the motion picture flop. It will be interesting to see how it plays out on one of the largest stages in the states. It's filled with amusing dialog and packed with catchy songs, so it promises to be a engaging night under the stars.
Great American Trailer Park Musical - Stray Dog Theatre 8/2-8/18
While I haven't seen this particular musical before, Stray Dog Theatre has started to regularly feature musicals in their seasonal lineups. They excelled with their spectacular version of Tommy last year, so this could be another winner. It certainly has an intriguing title.
The Lion King - The Fox Theatre 8/15 - 9/2
The Lion King is a wonderful show with eye-popping visuals. I'm hoping to bring my young son along so he can see how the animated feature was transformed for the stage. I suspect he'll be in awe of the work the performers do to bring these cartoon characters to life in such a unique fashion.