Hover Kart Racing and hover kart battle are candystand games which are powered by a free service called OMGpop. This service allows you to play casual multiplayer games.
In Hover Kart racing, you attempt to get around the track several times before everyone else does. You can drive over smileys along the way to collect items that you can use for your own benefit or to the harm of other players. you can also press shift while going around a corner to "drift", filling up your drift meter and earning a free boost.
In Hover Kart Battle, the focus is on the items. This time you are in an arena, using the items as weapons and attempting to take away all three of your opponents' lives. last one standing wins.