SIOUX FALLS, S.D. (KELO.com) -- An anonymous donor has laid a $25,000 challenges--which if it works--could turn into an extra $50,000 for the Children's Miracle Network's Radiothon. KELO-AM's sister stations have been broadcasting from 6 a.m. to 6 p.m. yesterday and today in support of the radiothon. Last year, the event raised $216,000. This year, according to CMN officials, if the event his $241,000 by 6 p.m. today, the anonymous donor will kick in another $50,000.