I think this was meant to be posted on the Spider and Arachnid Identification board. :-)
Where (geographically speaking) was this spider?
It would be hard to identify the species from that photo, because it is rather dark, but I can say two things for certain: (1) it's a male (2) it doesn't appear to be one of the medically significant spiders that is found in the U.S.
Perhaps one of the experts can tell you the family based on the shape. (I'm more of an amateur, so I can't do as much with low-quality images.)
This appears to be a male cobweb weaver in the genus Steatoda, but I cannot be positive based on this one image. Male spiders of nearly all species wander in search of mates, making them more difficult to identify in the absence of a web, habitat, etc.