The largest and most commonly observed species is the “catface” or “monkeyface” spider, Araneus gemmoides. Large females may be more than .25 inch in diameter and are generally round with a prominent pair of humps on the back. Araneus spiders are harmless.Source: http://www.ext.colostate.edu/pubs/insect/05512.html

Members of the leaffooted bug family, they eat seeds and do not bite people. They enter homes in search of warm, protected sites to overwinter. This habit is shared by many other insects, such as boxelder bugs and elm leaf beetles. They do not reproduce in the home or damage household items. Conifer seed bugs usually die in a week or two if not allowed to drink water.

The “widow” spiders are a group of related spiders in the genus Latrodectus. Several species occur in the United States, but the western widow, Latrodectus hesperus, is the overwhelmingly dominant species throughout Colorado. (The “true” black widow, Latrodectus mactans, is more common in eastern and southern areas of the country.)