Most likely a woodlouse spider. They're pretty common but like dark corners and don't tend to come into houses.
you have found aRED BACK SPIDER! watch out. poisonous
A black spider that has a red stripe on the back is possibly a red spotted ant mimic spider. They walk on six legs instead of eight and can be found in Arizona.
A black spider with a red back and thick fuzzy legs is commonly called a jumping spider. The formal name is Phiddipus audax.
The eastern mouse spider is an arachnid whose body is blue and red and whose legs are black. The red-headed arachnids in question (Missulena bradleyi) may be black- or brown-bodied if female and blue-bodied if male. They will be found natively only in coastal eastern Australia.
A ladybird spider is a spider whose red body has four black dots.Specifically, the spider in question can be found natively in Greece. It carries the scientific names Eresus cinnaberinus and E. sandaliatus. It has white-striped black legs. Its fused head and thorax (prosoma) is black. Its abdomen-like rear (opisthosoma) is red, with 4 black dots.
A black widow
tarantula
It can be hard to tell what kind of a spider you are looking at that has a red head and back and black and white striped legs, since the body type is also an important factor. Chances are that it is a red-headed jumping spider, which can cause a somewhat painful bite but is not otherwise dangerous to humans.
The Red-back spider (Latrodectus hasselti) is commonly found in Australia. They are a small black venomous spider with long thin legs, and the females have a red stripe on their globular abdomen.
A spider that has a red upper body and legs and a gray lower body is a sowbug killer spider.
that sounds very possibly like a mouse spider
http://en.wikipedia.org/wiki/Redback_spider