"The Alphabet Song," "Ten Little Monkeys" and "Baa Baa Black Sheep" aren't typical accompaniment for a morning workout, but they're appropriate when your exercise partner is not yet 3. They formed the soundtrack recently at the Mall of America as mothers pushing babies in strollers zipped through Nickelodeon Universe, practiced plyometrics at Lego Land and cooled down in front of the Rainforest Cafe - bringing the mall to life even before its stores opened.