Audience members love old-fashioned musicals because they tend to be light and happy and you can whistle the final number as you head blithely out the door.

Theaters love them because, well, because audiences love them, and the phone in the box office never gets a rest.

But producing a musical can bust a little theater's budget. That's where the Winter Park Playhouse comes in.

The little playhouse, which has just opened its first season at the northern end of Orange Avenue in Winter Park, has joined the slim ranks of Orlando-area theaters that produce musicals -- and the even slimmer ranks of professional theaters that regularly produce musicals, the Mark Two Dinner Theater being the only other one.

The playhouse's production of I Love You, You're Perfect, Now Change is the kind of show that most of the folks who love musicals crave.

The lightweight little revue plays up both the charms of the four cast members and the easy way they have of making you laugh. If that's not a recipe for success, I don't know what is.

I Love You, You're Perfect, Now Change may be new to Orlando audiences, but it has been a long-running hit off-Broadway for its creators, composer Jimmy Roberts and book-writer and lyricist Joe DiPietro, who also wrote the popular comedy Over the River and Through the Woods.

So it's perfect fodder for the Winter Park Playhouse, a small performance space that has dedicated itself to producing small musicals and the occasional nonmusical play.

Sharing a storefront with the Master Class Academy, a theater school operated by the same folks, the playhouse is currently set up in a small, high-ceilinged, black-draped room with a tiny, makeshift-looking proscenium stage. (Plans are to build tiered seating for 86.) Eventually, the metal folding chairs will be replaced by padded versions: At I Love You, You're Perfect's opening night gala, director Michael Edwards auctioned off four of those more comfortable numbers for $45-$60 apiece.

So far, the production values are also at something of a minimum. In this show, musical director John B. deHaas and violinist Sharon Knapp are positioned center stage, and the four actors must maneuver around them and the furniture, which mostly consists of four wooden chairs. The actors' many costumes are unexceptional, and the special effects consist of a "sign girl," an attractive young woman dressed like a kitschy figure on a Valentine's cake, who strolls through before each scene and places the scene's title on an easel.

Yet the mild-mannered humor of the show is likely to win people over from the start, when two traumatized-looking couples -- Roy Alan, Heather Alexander, Michael Colavolpe and Colleen Renee Wilson -- dress for a first date. I Love You, You're Perfect takes you through nearly all the excruciatingly familiar steps of courting and matrimony -- the politeness of early dates (in "Men Who Talk and Women Who Pretend They're Listening"), the pains of dining with prospective in-laws, the vigilance of first-time parents, the tentativeness of meeting someone again after your spouse has died.

I Love You, You're Perfect may not boast memorable tunes or piercing insights about the joys and pains of relationships. But this mild-mannered revue puts a clever twist on the mundane (note how one attorney manages to worm his way into the bedroom), and the low-glamour quotient of the very able actors makes their situations all the more real.

Take Wilson's stricken bridesmaid, forced once again to appear in public in a hideous dress she'll never wear again. Or take Colavolpe's childless single guy, appalled to see what a baby has done to his best friends.

The rubber-faced Alan plays up the comedy (note the nerdy misfit he plays in one early scene). But it's Alexander who brings a note of humanity to the show: She's especially touching -- and more than a little fierce -- as a recent divorcee who's ready to begin the dating game all over again, but this time on her own terms.

I Love You, You're Perfect may turn a little schmaltzier than it needs to, and the staging could use some tweaking: Moving the musicians from center stage might remove some visual distractions and give the actors room to move.

But Winter Park Playhouse may have a winner on its hands -- a show that's pleasant, palatable and stays with you no longer than an after-dinner mint. It can't be a coincidence that I Love You, You're Perfect, Now Change has opened in time for Valentine's Day. I suspect that more than one pair of sweethearts may see themselves onstage.