Many yoga studios in and around Chicago are offering free classes Sat 1/23 as part of Yoga Day USA. At REI (1466 N. Halsted), classes include vinyasa at 10:30 AM, hatha (men only) at noon; gentle at 2 PM, and ashtanga at 4 PM. Global Family Yoga (1207 W. Bryn Mawr) is offering a children’s class from 1 to 2:30 PM and a family class (ages five and up) from 3 to 4:30 PM. Echo Yoga Studio (1925 N. Milwaukee) in Bucktown is also offering a free class from 10 to 11:30 AM. Yoga Day USA’s Web site lists other local freebie classes.