Former wunderkind Mark Morris, now approaching 50, made his reputation with L'Allegro, il Penseroso ed il Moderato in 1988, when the Mark Morris Dance Group had just become the resident company at the Theatre Royal de la Monnaie in Brussels. But despite making appearances here since the mid-80s (originally at the tiny MoMing Dance & Arts Center), he and his troupe have never brought L'Allegro to Chicago until now, under the auspices of the Ravinia Festival. Set to an oratorio by Handel based on Milton's poems, the piece is big, employing 24 dancers, an orchestra, a chorus, and four solo vocalists (live music here will be provided by Chicago's Music of the Baroque). Moreover, it is, by all reports, exquisitely accomplished: a few years ago New York Times critic Anna Kisselgoff called L'Allegro Morris's "happiest and best work," and Steven Winn in the San Francisco Chronicle wrote that "as much as any great work of art I know, this one captures the intensity and wondrous bafflement of human experience." But don't go expecting only high-flown sentiments and lofty, dignified choreography--that's not Morris's way. The piece also includes a fox hunt with the dancer hounds on all fours, butt slapping among courtiers, and dogs peeing on trees. 8/26-8/28, Fri 8 PM, Sat 7:30 PM, Sun 2 and 7 PM, Harris Theater for Music and Dance, 205 E. Randolph, 847-266-5100, $30-$75.