Mention Leonard Bernstein musicals, and you’re probably already thinking “West Side Story.”

But 13 years before “West Side Story” made its Broadway premiere in 1957, the New York composer composed the music for “On the Town,” a slender, sweet and funny musical whose music was based on Bernstein’s score for a ballet,  “Fancy Free,” which also was first performed in 1944.

This year’s Oregon Festival of American Music — in its 25th anniversary season — kicked off Friday night at Eugene’s Shedd Institute with a production of “On the Town” in the Jaqua Concert Hall. It’s the opening number in the Shedd’s three-show series of musicals, which continues with “Oliver!” (September 16-October2) and “Annie Get Your Gun” (December 2-18).

I was happily surprised this evening by the gentle good quality of OFAM’s “On the Town.” It’s a show that essentially has six lead roles, three boys and three girls, all of whom need to be able to act, sing, and dance, and the Shedd has managed to pull off this unlikely feat in style.

The story is simple. Three sailors find themselves on liberty for 24 delirious hours in New York City, and all three try to compress all of life and romance into that single amazing day — mostly in the form of boy meets girl. Gabey, particularly, falls in love with a photo he sees on a subway of Miss Turnstiles for June, and enlists his two buddies into the citywide search for the charming Ivy Smith.

The best known — perhaps the only known — song in the show these days is “New York, New York,” as in “New York, New York, what a hell of a town,” a lyric often bowdlerized (though not here) to “a wonderful town.”

The production, directed by Peg Major with music direction by Robert Ashens, keeps the action and music moving right along. One of the best scenes comes at the end of Act I, when a sexy encounter between Stephanie Hawkins (as Claire de Loone) and Jim Ballard (as Ozzie) devolves into natural history museum madness.

Janet Whitlow’s set, with large New York silhouettes, is simple and effective. Caitlin Christopher’s choreography takes good advantage of several trained ballet dancers in the show.

“On the Town” runs through August 7. Go see it.