There is a geyser called Lady Knox that goes off at about 10.15am daily near to Rotorua, New Zealand.
This attraction is part of the "thermal wonderland" of Wai-O-Tapu. It normally costs NZD 32 for the admission. However, since the geyser is outside the rest of the park, you can watch it for FREE if you know where to find it (just ask around, its about 2km away).
This geyser would normally erupt once every few days, but a staff from the park help set it off by adding some detergent into it (eco-friendly detergent, apparently).
It doesn't erupt immediately after adding detergent. It still took about 10 minutes before water shoots out and mixes with the cold air to have lots of steam surrounding it. But it was pretty cool anyway. The other place you can see geysers is in the US.