While fairly easy to figure out how they get their name, jumping spiders are known for their ability to jump. They are only about 1/8 of an inch long, but they have been shown to be able to jump 10-50 times the length of their body. They are able to accomplish this by increasing their blood pressure in the third and fourth sets of legs. They do not hunt with webs as they use their jumping abilities as their primary method of hunting prey.
They are not normally found inside as they prefer to hunt in areas that are thick with cover such as areas with heavy grass and or in gardens. While they typically try and avoid humans by running away when they are close, they can still bite. Their bites are not poisonous so no medical treatment is needed, however if you are bitten and the bite has symptoms that last longer than a day, you should consult a medical professional.