I mistakenly sprayed outdoor bug spray in the basement and the fumes and smell are extremely strong. They are coming through the vents and now my entire home is being affected. What do I do, other than open windows?

Other than opening windows there isn't too much you can do rather than wait it out. Although next time you might look into some ant or roach spray (http://www.domyownpestcontrol.com/roach-spray-c-2_71.html) that doesn't have such a strong odor, sometimes reading the reviews before you purchase can help you to know which ones smell worse than others.