This striking bug is the Large Milkweed Bug, Oncopeltus fasciatus. If I'm not mistaken it's one of the four main insects trying to get into homes at this time of year. The other three are lady bugs, stink bugs, and I think the fourth is a walking stick but you have to live around the right forests for them.
This lone bug was at our street light one day. As colorful as they are I'm happy I only saw one of them. This insect, along with a few others, feed on milkweed seeds and when they hit, they can hit big. They crawl all over the plant to meet members of the opposite sex and occasionally certain plants will get mobbed by them. So while it's neat to see one or two of them, a small swarm can be quite the nuisance in the garden.
Something I wish I had a picture of though is their young on a plant. Young nymphs to this species actually look like milkweed seeds. And when a fresh milkweed pod opens the young bugs will enter and line themselves up, usually all in the same direction, and as they feed they actually mimic the cluster of seeds they're feeding on.
Apparently these insects can be bread in captivity and fed a steady diet of opened (unsalted) sunflower seeds.