Highly recommend checking out this museum while you are in town. Lots of cool exhibits but our favorite is the butterfly house and insectarium. We have a discounted rate for the 30th, 31st and 1st of $12. Just make sure you let them know you're in the Welker-Duffy wedding at the front desk.
Located on Duke's campus, this is a great place to spend some time perusing beautiful flowers and lounging near Lilly ponds. Emily and I used to spend time here when we both worked at Duke. We recommend bringing a blanket, snacks, and frisbee for an afternoon picnic.
If you're looking for something fun to do Thursday or Friday night - go see a Bulls game! The stadium is right near the Aloft and in the middle of downtown. Games are a lot of fun and this is something we love to do on a nice summer night in Durham. http://www.milb.com/schedule/index.jsp?sid=t234
One of the best places to go have a beer. They have board games there, are dog friendly, and usually have a food truck parked outside. It's right across the street from the wedding Venue, and just a few blocks from downtown.
Fancy coffee shop with lots of outdoor seating, located right around the corner from the wedding venue.
Our favorite pizza place in Durham. Was just a food truck until a few years ago they finally got a restaurant. Located downtown near a bunch of good bars and shops.