There's a lot of good hiking near Wolfeboro. As mentioned already, the Belknaps have a ton of great hiking - in fact, there's a patch you can get if you finish the
12 peaks
Copple Crown has a trail up from the north side of the mountain, near Moose Mountain. [url=http://www.franklinsites.com/hikephotos/NewHampshire/copplecrownmtn.php]. There's also a herd path along that trail that goes to the lost Copple Crown ski area.
The Ossipees have some great hiking (beware of the ticks). I especially recommend Mt. Roberts from the Bottling Plant, as well as Mt. Shaw/fake Black Snout via the Big Ball Mountain Trail.
If you're willing to drive a little more than half an hour, you're at the foot of the Sandwich Range. Mt. Chocorua, Whiteface/Passaconaway/etc. all offer many longer hikes.
You can also cross over the border into Maine and do Burnt Meadow Mountain and Mt. Cutler. Both are very scenic moderate hikes, probably about half an hour from Wolfeboro.
Let me know if you have any questions on these - I hike this area 10-15 times a month.