$35 plus shipping and handling from Breakthrough Sports, 249 E. 48th St. Suite 6C, New York, N.Y. 10017, phone: 212-759-5352, Internet: http://www.bathroomtennis.com/

If you are like many people, you often ask yourself: ``How come I cannot play tennis as well as top stars such as Venus Williams and Andre Agassi, even though I own a racket and have taken several lessons? What is the secret to their success?''

We can answer that question in two words: ''Bathroom Tennis.'' We realize that this sounds like some kind of kinky pervert game wherein the players would. . .OK, never mind what the players would do.

But in fact, Bathroom Tennis is a scientific product designed to improve your tennis game in your bathroom, with the help of an instructional shower curtain. Really. According to the instruction manual, while you are in the bathroom, you're supposed to study this shower curtain, which shows you how to make various tennis shots, then you're supposed to visualize yourself making this shot on a tennis court, and this will cause scientific things to happen that will make you a better tennis player. As the instruction manual states: ``. . .anytime you are brushing your teeth, sitting on the commode, or scrubbing in the tub, you can get in some valuable practice time.''

We have absolutely no doubt that this training system is used by all of your world-class players. We bet if you were to go into the locker rooms at Wimbledon, you'd see the competitors lining up to get into the bathroom (or, as it is called in England, the ``lorry'').

So we strongly recommend that you buy this gift for the tennis player on your list who has (1) a sincere desire to improve his or her game, and (2) a commode. Buy one for yourself, too, and get ready for some exciting workouts! Be sure to wash your hands afterward.