If you want to do something really memorable a visit to Orakei Korako (“place of adorning”), a geothermal park 25 minutes drive north of Taupō is a great option. It has 27 geysers, multi-coloured thermal terraces, mud pools and caves set among native vegetation. You have to lake a short boat trip across the Waikato River to visit the park. There is a ferry available on demand from 8.30am until 4.00pm.
To get there from Taupō take State Highway 1 for about 14 kms north from the Wairakei roundabout. Turn right onto Tutukau Road and after 9kms turn left onto Orakei Korako Road. The carpark is 5km along this road at the end.
This is a link to the attraction’s website.
If you want to make a special experience even more interesting you can go with Taupō Kayaking Adventures and add a visit to “the squeeze” a natural hot water spring and waterfall. This is located downstream from the tourist area and is only accessible if you have a boat. To reach the hot waterfall you have to wade up a stream cut into a relatively narrow channel in the volcanic rocks. It’s from this it gets the name “the squeeze”. The trip starts at the kayak operator’s base opposite the beach at Acacia Bay North.
This is a link to Taupō Kayaking Adventures’ webpage about this trip.