This is a male Western Black Widow. The female is all black, with the hour-glass figure on the bottom, but the male has this different color pattern on the abdomen. Males are harmless and have no venom. Females are venomous, and can even be dangerous. It was found on 5 September 2011 while digging up some ground to plant Irises in Colorado Springs.
orchid spider looking big on his web; these spiders are useful if you want insects caught as they 'position' their webs in flying insects' paths, even re-positioning the webs to an outside spot determined by light insects are attracted to from your homes - they are out in the day time but are less active but then so is their food source