11^th Annual Chattahoochee Challenge 10K and 1-Mile  Fun Run, official Peachtree qualifier along the Chattahoochee River benefiting the Chattahoochee Nature Center.  10K starts at 8am.  $27 until February 9 or $32 race day.  1-Mile Run:  7:30am.  $15.  Register at any Big Peach Running location or online at www.active.com or www.chattnaturecenter.org.  Chattahoochee Nature Center, 9135 Willeo Road, Roswell.  More info/parking info:  770-992-2055, ext. 226, or www.chattnaturecenter.org.