Awesome, free, installation art gallery. It's open during lunch time during the week also(Wed-Sat) so it's the perfect alternative to a lunch(Or you can go to the street cart right outside of the door!). Go into the station and take the small elevator up to the second and third floor. The staff usually won't acknowledge you, but oh well, just walk around and take a peek - the still is always pretty interesting.
The current exhibit is recent icelandic art called 'Long are the Days, Short are the Nights'. There is also an another piece to this exhibition open at 943 Liberty Ave on Friday and Saturday from 11am-8pm or so called Paths. It's a pretty cool exhibit, some interesting stuff being done. I liked Paths, Converge, and Rotating Unit quite a bit