Nelson is close 110 min drive, 50 min by fast boat to the Abel Tasman National Park (http://www.abeltasman.co.nz/) which offers sea kayaking (http://www.seakayaknewzea...) and the 51 km Abel Tasman Coast Track (http://www.doc.govt.nz/pa...) one of NZ's Great Walks (http://www.doc.govt.nz/parks-and-recreation/tracks-and-walks/great-walks/). Also see Tramping in New Zealand.
Visit the district museums in Collingwood, Motueka, Takaka and Murchison.
There is a terrific new Museum on the corner of Trafalgar and Hardy Streets that offers free admission to locals and by donation to outsiders that is open 7 days a week until 5PM. Closed 25 Dec.
Go swimming in the river up the Maitai Valley or Lee River Valley! You can hitch hike up there if you don't have a car. Bring a sandwich and some water.
