There's something reassuring about our ability to transform nearly everything on earth into a disco. Thirty years after the last train pulled out of the old Milwaukee Depot, this steely monument to the industrial age still looks like something out of a Monet painting. But inside the muscular metal arcade--built a century ago to shelter our mightiest locomotives--there is an ice-skating rink, complete with mirrored balls, speakers that pipe Cher, Cher, Cher, and a hot-dog stand. The song sets could use some help from one of our better club DJs. (When Madonna's "Music" piped up one day, a figure skater was heard to exclaim, "Finally! Something not from the Eighties!") And, yes, the public-skating hours are difficult to memorize. (Through June 17, the rink is open Monday through Thursday, 11:00 a.m. to 1:15 p.m., 9:00 p.m. to 11:00 p.m.; on Friday from 11:15 a.m. to 1:15 p.m., and from 8:30 p.m. to 1:00 a.m.; on Saturday from 11:45 a.m. to 1:15 p.m., and 6:45 p.m. to 1:00 a.m.; and on Sunday from 9:00 a.m. to 10:00 p.m. After June 17, hours will be extended further. Got that?) But the train-shaped Zamboni is to die for (or laugh at). For a cheap admission price ($5 for adults; $3 for skaters under 17) you and your friends can try couple-skating, group skating, or solo flopping. The showoffs in the rink's center are usually happy to offer tips. Beer and cocoa are available to the injured. And, of course, there's always Cher.