Simulator Golf for 4 at Ingleside Golf Club, 104 Horseshoe Lane, Thorndale, PA.

On a real golf course, you'd step up to the tee, grip theclub properly with both hands, spread your feet shoulder-length apart and take your swing. With any luck, you'll hit the ball, launching it into the air and then onto the green.

With a golf simulator, the procedure is very much the same, except you're standing on a platform, called a swing pad, in front of a projector screen. The swing pad often has fake grass and a tee to simulate real-world conditions. At the same time, the screen displays a realistic image of a golf course, complete with grass and skies. You step up, swing, and hit the ball right at the screen, just as you would at a driving range.

The screen is connected to a computer with sensors designed to calculate every aspect of your shot. Usually, an array of light sensors, radar and other motion tracking devices are placed around the border of the projection screen. The tracking systems on some simulators include one or more 360-degree curtains of infrared beams, emitted at 60,000 pulses per second, which immediately analyze the ball as it flies [source: Sportnetting.com].

Once your ball strikes the screen, the information collected by the sensor array is sent to the computer. It's there that a variety of factors involved with your shot are evaluated -- speed, shot angle, distance, spin, trajectory and so on [source:aboutGolf.com]. Some systems even use infrared optical sensors to monitor your swing movement and offer guidelines on how to improve.

But this simulator is more than just a computer that tells you how far your shot goes. You can designate which course you want to play on, and many of them are modeled after real-life golf courses, such as Pebble Beach. In addition, you can control the wind velocity and weather conditions on the course. Imagine being able to perfect your swing in the rain without ever getting wet!