Dogfish Head Brewery is an east coast Mecca for craft beer fans and tour of the facilities and a sample of their seasonal brews is a must if you're in the Milton, Delaware area. The brewery tours are first come first serve and the crowds of interested beer-fans are growing by the day so make sure to get there early if you want to catch one of the tours. The tours take place hourly during the week from 11AM to 4PM and they extend into the evenings on Thursdays. It's a good way to get a behind-the-scenes look at the brewery and see a bit of its inner-workings.
Another plus is that all guests 21+ get to sample some of the craft brews whether they take a tour or not (that doesn't mean that you shouldn't take the tour, of course!).