Colle+McVoy, located in the capital of the advertising state (Minneapolis, MN, of course!), is a prime example that you don't have to be a small firm to maintain a quirky, fun, and personable approach to design. In fact, they've made a rather large business out of staying true to "small-studio" style designs, using guerrila and non-traditional marketing as one of their many creative outlets. Great, youthful approach to a site for an ad agency that employs 170 creatives (2007), and was founded in 1935.
Clients: Red Wing Shoes, Erbert and Gerbert's, Nestle Purina