People, primarily white males between the ages of 10 and 30, with double ended skis and usually wearing baggy coats and snowpants ski down a run full of features such as kickers(ramps), designed to launch the skier into the air to facilitate tricks usually involving spins and flips, accompanied by grabbing hold of one or more skis, and landing as safely as possible on a downhill slope called a transition.Failure to land on the transition is responsible for many park-skiing related injuries. Kickers are found in many different sizes for different skill levels, and have transitions that sometimes vary in their position in realation to the jump (insert description of step-ups, step-downs, step-overs, gaps, etc.) Grind rails, which resemble stair railings are also found in terrain parks, in various heights, shapes and sizes (insert description of said shapes and sizes here) for different skill levels. These rails are designed for skiers to ride with their skis perpendicular to the rail. Spins are often incorporated into rail slides. Half pipes are another common feature of terrain parks. They resemble a U shaped ditch and are designed for skiers to perform aerial maneuvres out of by skiing up the walls, catching hang time and hopefully landing back on the wall. a variation on teh halfpipe is the quarter pipe, which is only one wall of a halfpipe, hance its name. Examples of terrain parks can be seen on television during the X games winter sports competition, held annually.
theres a start for ya anyway. good luck.