Orchard Orbweavers (Leucauge venusta) are common, generally not noticed, and absolutely beautiful! They weave those intricate orb webs that catch the dew in the mornings and insects at night. The webs are most often placed in a sunny area between plants or branches and can be about a foot in diameter.
These spiders are not harmful to people.
This picture was taken May 28, 2012, in Green Lane, Pennsylvania, USA>
A map of their range is here – basically the eastern half of the USA