The Auditorium Theatre, a joint project of Louis Sullivan, Dankmar Adler and Frank Lloyd Wright (who served as an apprentice draftsman) is one of those places you're destined to see a show in if you're a Chicago theater buff.
While Chicago is known for small, personal theaters, the Auditorium isn't one of them (it seats 4,300). Originally home to the Chicago Symphony and the Lyric Opera, it now hosts many of the traveling Broadway musicals and big-name concerts (along the lines of Wilco and REM), so if you want to see Les Mis, you've gotta pay the price. Speaking of price, the nosebleed tickets are the cheapest, but for the most part not worth it (though the acoustics are great for the size). Either spring for better tickets or rent the Liam Neeson/Uma Thurman film adaptation.
It serves watered-down, overpriced gin and tonics during intermission. It's not all bad: very L-accessible, and if you have decent (orchestra) seats, its a wonderful theater experience.