The off-Broadway sensation Blue Man Groupbegan selling out the Charles Playhouse's Stage I as soon as it arrived in 1995. Famous for reducing even the most eloquent theatergoer to breathless sputtering, the trio of cobalt-colored entertainers backed by a rock band uses music, percussion, food, and audience members in its performance. It's not recommended for children under 8, but older kids will love it. Shows are at 8pm Wednesday and Thursday; 7pm Friday; 4, 7, and 10pm Saturday; and 2 and 5pm Sunday (check ahead for extra performances during the holidays). Tickets are available at the box office and through Ticketmaster.

Shear Madness, on Stage II (downstairs), is the longest-running nonmusical play in theater history. Since January 1980, the zany "comic murder mystery" has turned the stage into a unisex hairdressing salon -- and crime scene. The show's never the same twice; one of the original audience-participation productions, the play changes at each performance as spectator-investigators question suspects, reconstruct events, and then name the murderer. Performances are Tuesday through Friday at 8pm, Saturday at 6 and 9pm, and Sunday at 3 and 7pm.