Here are some good suggestions:
Prickles
Prickley / Prikkly
Prickley Pete
Pricky
Pokey
Pinch
Spanky
Cactor
Cactuar
Cacti
Follow these steps on How to Care for Indoor Cacti, shared by SFGate:
Pot a desert cactus in a mix of 1 part peat moss, 1 part garden soil and 1 part sand, or a prepackaged mix designed specifically for cacti. Transplant in the spring after the cactus has grown within 1/4 inch of the sides of the pot, but don't allow it too much extra space -- the next pot size up will be adequate.
Place indoor cacti in a window facing south, if possible. Choose an east- or west-facing window otherwise. Supplement with additional bright light for a total of 12 to 18 hours a day during the cacti's growing season to encourage flowering. Maintain relative humidity of 10 percent to 30 percent and a temperature between 65 and 90 degrees Fahrenheit -- glass windows with direct sun can get extremely warm, so keep a thermometer nearby. A hygrometer will help you keep tabs on humidity.
Water cacti when the top 1/2 inch of the growing medium is dry to the touch. Soak the medium thoroughly and allow it to drain when watering -- do not leave the cacti constantly sitting in a dish of water, as this encourages rot. Feed cacti from spring to fall with 5-10-10 fertilizer every two to three months, but do not feed immediately after transplantation.
Move cacti to a location where the temperature ranges from 45 to 55 so they can go dormant for the winter. Water sparingly and from the bottom, just often enough to keep the plants from shriveling -- even watering once a week may be excessive, depending on the plant and growing medium. Stop feeding cacti during their dormant period.
Check out some Tips on Growing Cacti from CactiGuide.com.