Do you compost? You should, if you have any outdoor space at home. All day Saturday, the University of Illinois Extension is selling compost bins worth $80 for only $25 to Chicago city residents (bring proof of address with you) at the Garfield Park Conservatory visitor parking lot. Why compost? Besides creating stuff that makes for really good garden soil, it's a simple and environmentally sound way to divert yard waste and vegetarian kitchen scraps from garbage dumps and sewage. Slowdown has the details on this virtual giveaway. UPDATE: Bins will also be available at the Chicago High School of Agricultural Sciences at 3807 W. 111th St. and the North Park Village Nature Center at 5801 N. Pulaski. (Thanks, Amber!)