Explore the marina, visit the Farmer's Market, and don't forget to take in Victoria Hall - an imposing architecturally significant building that dominates the downtown.
Cobourg and area is an antique hunter's delight, with everything from architectural salvage to early Canadian furniture to vintage clothes. Port Hope is only 10 minutes down the shore, and it too is a great place to poke around in interesting shops and dine in intimate restaurants and pubs.