MELVIN DURAI'S HUMOR COLUMN - "BEACHES OFFER ALL KINDS OF FUN" I just spent a fabulous weekend at the beach, where I joined thousands of people, many of whom had driven several hours and rented expensive rooms for the opportunity to lie around on the sand. Sure, they occasionally cooled off in the ocean, but they spent far more time on the sand. Beaches are full of sand and, as I've come to understand, it's high-quality, government-approved sand. If they sold such sand in a store, it would cost at least $10 a pound and you'd be limited to three bags. But at the beach, you can kick it around, dig holes in it and use it to build castles. If you so choose, you can even bury your mother-in-law in it. Temporarily, that is. Until some kid digs her out. Most folks set towels or chairs on the sand, so they can plant themselves under the sun and try to get a tan, while pretending to read a book. What they're really doing is checking out all the people around them. Beaches are ideal for that because the rules require all people, even Republicans, to wear as little clothing as possible. If you're wondering why, the answer is simple: The less you're wearing, the easier it is to swim in the ocean. Wear a three-piece Armani suit and you're almost guaranteed to drown. And the lifeguards may even have trouble saving the Armani. So if you're at a beach and a lifeguard points at you, while blowing his whistle, it probably means you're wearing too much. Do everyone a favor and remove something immediately. Of course, beaches have a lot more to offer than scantily clad people, as my two friends and I discovered during our weekend at Bethany Beach in Delaware, a state so small that Carl Lewis used to practice jumping over it. I mention the size of the state not to insult Delawareans, but to try to explain why my friends and I had so much trouble finding a parking space. We drove around for what seemed like hours, before finding a space that was within the same ZIP code as the beach. But it was all worth it, for we had lots of fun. We sat on the sand, reading magazines and sipping soda. My friends tried to gain tans and I tried to enhance mine. I'm now so dark, I need to smile to remain visible at night. When we weren't tanning, we were splashing in the water or eating french fries. Fries are essential at the beach, because they're full of carbohydrates and give you enough energy to stand in line for hours at the rest rooms. When they weren't standing in line, my friends, both intelligent young women, were conducting scientific studies. Here are some of their findings, which you'll soon see in the Journal of American Beaches: ---There are too few cute guys at the beach. And most of them are lifeguards. Too bad we're not drowning. ---There are too many pretty women at the beach. Too bad they're not all fat. ---Some women should not be wearing bikinis. They should be wearing curtains. ---No man should be wearing Speedos. We'd rather use our imaginations than be immediately disappointed. ---A smart woman always brings a man to the beach. When he's not carrying your stuff or rubbing lotion on you, you can always send him for more french fries.