Stage magicians are routinely billed in hyperbolic terms: the Amazing So-and-So, Such-and-Such the Great. Penn & Teller, in keeping with their wryly understated style of humor, describe themselves as "eccentric guys who know how to do a few cool things." In fact, this pair of postmodernist prestidigitators, transform the well-worn craft of illusionism into highly theatrical performance art. In their current "Refrigerator Tour," which features a set by the masterful Broadway designer John Lee Beatty, they put a conceptual spin on such classic devices as the Sword of Damocles (here updated to a 450-pound refrigerator), handcuffs, card tricks, psychic power, sawing bodies in half (in a clear plastic box yet), Indian fakir feats, and animal routines (among the new bits on this year's tour is an ancient Buddhist "duck trick"). Reveling in the wonder and the fraud of their genre, they simultaneously celebrate and debunk the traditions established by tricksters from Houdini to Henning, Cagliostro to Kreskin. The more they expose the craft behind their art, the more magical it becomes. Chicago Theatre, October 29 through November 3 (175 N. State, 559-1212). Monday-Thursday, 7:30 PM; Friday and Saturday, 7 and 10:30 PM. $17.50-$27.50.