Easter eggs and rabbits weren't the only things Washington's small ones had to choose from yesterday morn. Sunday was also the opening day of the Kennedy Center's fourth annual Imagination Celebration, a two-week-long national children's arts festival featuring clowns, dancers, mimes, musicians, actors and puppeteers.

The celebration began in the plush red Grand Foyer. Hordes of toddlers in bonnets and minaiture three-piece suits, along with parents and friends, clustered about a makeshift stage that literally throbbed with the rock and fusion sound of Earth Song, a four-piece band. Some kids clutched their ears; others jumped onstage and joined in the group's music. Clowns and human-sized Easter bunnies meandered through the crowd, coaxing shy babes onto the dance floor, juggling bowling pins and passing out candy and balloons.

Later that day in the Musical Theater Lab, The Living Poem, a quartet of clowns from Greenfield, Mass., performed a rowdy, fast-paced program of well-beloved schtick. For example: one clown played a slew of silly tunes on the piano, another attempted again and again to balance on a paper cup, a third schlepped woefully around and sang in a buzzy voice and a fourth, the sole lady jester, ate wiggly fish out of a pail. Needless to say, they were quite a success with the younger set.

The Imagination Celebration continues today with performances by the Dance Theater of Harlem at 12:30 and 7.