Location: Atlanta, Georgia
Spider mostly brown, with black and white stripes. Would fit on a teaspoon. Ran quickly but not very far when I tried to catch it.
Click to zoom in the pictures below:
Image Source: Bug Guide
Males are generally thinner in profile than the females, which is well depicted below.
Image Source: Spiders.Us
Based on the pictures provided, you seem to have captured a male Dolomedes tenebrosus.