Le Cirque Invisible is a collaborative, fanciful mini big top that for two whimsical hours piles goofiness on goofiness. More shtick than substance, it's nonetheless a performance full of wonderful contrasts: the ethereal and the coarse alternate as Victoria Chaplin (yes, she's Charlie's daughter) and Jean Baptiste Thierree take turns creating entertaining, surprising illusions. Chaplin's most remarkable creations are her costumes: she makes fantastical creatures out of flaps, strips, folds, and containers of cloth that snap together. An acrobat and an athlete, she wears her puppetlike clothes and dances on the tightrope with an expression of dazed innocence. Thierree plays the clown as comic failure, his pop eyes and jowly good cheer promising success even as he reveals the secrets behind his "magic." It's a winning combination, built on playfulness and sustained by Chaplin's brilliant designs. Athenaeum Theatre, 2936 N. Southport, 722-5463 or 902-1500. Through October 13: Thursday, 7:30 PM; Friday-Saturday, 8 PM; Sunday, 3 PM. $10-$36; half-price for children on Sundays.