Chicago, it turns out, has a number of relatively inexpensive hotels within walking distance of the Hyatt Regency. Some of these are listed here - the rates during the week of DjangoCon were determined on May 23, 2013, and are exclusive of taxes.
Wicker Park Inn $139 http://www.wickerparkinn.com/
Old Chicago Inn $ 35 http://www.centralloophotel.com/
Central Loop Hotel $131 http://www.centralloophotel.com/
Villa Toscana Guest House $119 http://www.villa-toscana.com/
Two Urns $93 http://twourns.com/
Parthenon Guest House $80 http://www.chicagoparthenonhostel.com/reservations/