Keep your eyes peeled at Isemarkt — you're bound to find some unique curio in one of its many stalls. After you've found the perfect gift, try some fare from one of the food vendors.
You'll have no end of sightseeing choices in Eimsbuettel. Isemarkt is an ideal place to start here, but there are plenty of other fine spots to enjoy. Hagenbeck Zoo, Volksparkstadion, and Hamburg City Hall are close to the community marketplace and will fill in your day nicely.