Often, summer musicals are to theater what cotton candy is to nutrition — sweet and fun, an only slightly guilty pleasure. And thank goodness for that.

“Hairspray,” which opened last weekend at Baton Rouge Little Theater, is a summer treat, a great way to take your mind off the ludicrous heat and humidity. The laughs are genuine, the singing is very good, and the audience leaves feeling these really are, in Corny Collins’ words, the nicest kids in town.

Well, most of them, anyway.

Certainly, Tracy Turnblad, played with perky charm by Marion Bienvenu, fits the description. The plus-size teen from a working-class, early 1960s family loves to dance and never misses Collins’ show, which is Baltimore’s version of “American Bandstand.” It’s where all the cool kids are — especially the dreamy Link Larkin (Andrew DiGerolamo) — and she sees it as her ticket to fame.

Bienvenu has the voice and enough dancing skills to be the character the audience will root for. Surrounding her is a cast that holds up its end of the bargain.

There have been times when, staging a musical that featured lots of dancing, theaters have to choose between singers with lead feet and dancers with poor voices. No such problem here. Director Keith Dixon, choreographer Avery Wilson and musical director Richard Baker found everything they needed in the 35-member cast.

Pleason Underwood and Cliford Johnson gave eye-catching dancing performances, and Johnson also excelled as a singer and comedic actor as Seaweed J. Stubbs, the black student whom Tracy meets in school detention. That encounter broadens both her dancing skills and her awareness of how talented black dancers only got on Collins’ show once a month.

Rosalind Reynard, as she has before, brings a powerful voice and presence as Motormouth Maybelle, Seaweed’s mother and host of the “Negro Day” on Collins’ show. Her solo in “I Know Where I’ve Been” is the show’s vocal high point.

Really, there were no poor performances. All of the major characters — Tracy’s parents, Edna and Wilbur (Lester Mut and Joe Boniol); Collins (Timothy Callais); the bratty Amber Von Tussle (Shelley Regner) and her witchy mother, Velma (Christine Miller); Tracy’s best friend, Penny (Danielle Smith); and Little Inez (Breanna Collier) — cast a strong shadow. It’s a tradition that a man in drag plays Edna Turnblad, and Mut milks the role for all it’s worth.

This play has a conscience — Tracy starts a crusade to integrate “The Corny Collins Show” — but it’s mostly just a lot of fun. The jokes are occasionally off-color, but nothing that any but the most prudish among us would find objectionable.

A musical with this many voices coming on and off stage must be a nightmare for the soundboard operator, and there were glitches on the opening Saturday performance. DiGerolamo’s voice is pleasant but not powerful, and it didn’t always get the boost it needed. The amplification afforded the Dynamites trio of Tyler Thomas, Shanna Marie Burris and Shenetra McKnight also was uneven.