Nike's newest shoe is the lightweight 3.0 Flyknit. Want to try before you buy? Slap on a trial pair and hit up a free Shred415 class at the Magnificent Mile Nike store at 669 N. Michigan Ave.

Pre-register for one of the store's eight free, 30-minute classes offered at 6 a.m., 6:45 a.m., 7:30 a.m., 11:30 a.m., 12:15 p.m., 5 p.m., 5:45 p.m., 6:30 p.m. or 7:16 p.m. on Thursday. Sign up for your free class online.