WHAT HAPPENS when the classic strains of Russian composer Peter Ilyich Tchaikovsky are blended with a cartoon show that is a hit with the preschool crowd?

The answer can be found tomorrow at Upper Darby's Tower Theater, which is hosting two performances of "Max & Ruby in the Nutcracker Suite."

While most folks are probably aware of "The Nutcracker," you likely don't know Max and Ruby unless you are the parent of young ones. For the uninitiated, the two are the stars of "Max & Ruby," which airs on cable's Nick Jr. channel. The characters were created by author Rosemary Wells for a successful series of books. Max is a rambunctious 3-year-old bunny rabbit; Ruby is his 7-year-old sister who is, by turns, Max's rival and confederate.

In the Yule-themed live show, the two bunnies enter a "Nutcracker"-inspired fantasy world after receiving a Christmas package from their Uncle Drosselmeyer (the name of Clara's toy-making uncle in the real "Nutcracker"). According to the show's creator, although built around established, ultra-popular characters, "Max & Ruby in the Nutcracker Suite" wasn't necessarily an easy production to conjure.

"My challenge was to be able to partner the story of the "Nutcracker" ballet with the beautiful music of Tchaikovsky, and have it told through the eyes of the bunnies," said writer-director-choreographer Patti Caplette. "It was also a challenge to bring the story to a very young audience, and to keep the entertainment flow for the parents in the audience too."

The goal for all theater, regardless of audience age, she reasoned, is to "find out who the audience is, try to keep all the elements that stimulate the imagination and [engage the audience's] attention span." To that end, she broke the program into two 30-minute acts (with a 10-minute intermission).

"We found that works really, really well," she said. "[The kids] get a chance to go to the washroom, get a drink of water, come on back for Act II where we can resolve the whole thing in 70 minutes.

"I also try to keep the pace of the music and the storyline flowing, not lingering too long in one place. Kids are very intelligent and super-fast-paced these days, so I try to keep up with that on stage as well."

While Tchaikovsky's music is the heart and soul of "Max & Ruby," the score also includes some original material and a show-ending series of Yuletide standards.

"I took the really sweet elements of 'Nutcracker,' the doll, the toy soldiers - I made them robots instead because Max loves robots - and I added a few extra songs to make it different and interesting. And we all like to have a Christmas medley at the end of the show; the elves do that," said Canadian native Caplette, who, as a longtime ballet dancer, regularly danced "The Nutcracker."

As far as she's concerned, few, if any, pieces say "Christmas" more.

"You hear the music playing and think of the sugar plum fairies and the land of the sweets and everything that comes along at [holiday] time. The 'Nutcracker' sums it all up."

Perhaps the greatest contribution of any live show aimed at kids is that it gets them away from tablet screens and video games and introduces them to the joys and wonders of live entertainment. That's a sentiment with which Caplette heartily concurs.

"I must say that for me and my cast, that's probably the most rewarding thing," she said. "If [the actors] do a meet-and-greet after the show, they might get a letter the next day from a child who's seen the show and who absolutely has fallen in love with the story. Or they fall in love with Max himself.

"A lot of the response I get from moms is, 'I've never seen my child watch [something] with such large eyes and happy face for a whole hour. Thank you so much for putting on these shows.'

"That's really rewarding for me."

Tower Theatre, 69th and Ludlow streets, 1 and 4 p.m. Saturday, $58-$27.75. Buy tickets at http:/ph.ly/maxandruby.

Pool party

 We're not sure this qualifies as "theater" (it seems more opera-ish to us), but "Tributaries - A Modern Cantata" certainly ranks as one of the more unusual, non-Fringe Festival efforts to come down the pike.

Staged in the now-empty Kelly Natatorium at Philly's historic Water Works complex adjacent to the Art Museum, "Tributaries" is billed as a work that "explores how water shapes our lives." It was created and composed by Craig Hendrix of the Agave Opera Company and Philly-based film composers Will and Brooke Blair, who scored the recent 2013 Cannes Film Festival entry, "Blue Ruin."

The program also includes a performance by The Silver Ages, a men's close-harmony vocal ensemble.

Kelly Pool at the Water Works New Mill House, 640 Water Works Drive, 4 p.m. Saturday, $120-$15, tributaries.ticketleap.com.