Heading out to the lake is a great way to spend a summer day. If you don't have a plan, however, your day at the lake can turn into a day sitting in sand, getting horrific sunburn, and watching others have the time of their life as you wish you would have thought of something fun to do beforehand. It's time, therefore, to plan.

Here are five ways to have a great time at the lake.

Boating. Don't have a boat? No problem. Most large lakes have one or more marinas that rent boats. Better yet, if you live near a large lake, you just might know someone who owns a boat and perhaps is looking for some companionship out on the water. If you're nervous about inviting yourself and your family, offer to pay for gas and to take part in preparation and cleaning before and after. The best part about going with friends—other than the money you'll save—is they're likely to have water skis, kneeboards, wakeboards, or inner tubes.

Personal watercraft. You may know these better as jet skis. Personal watercrafts allow you to explore large areas at a high rate of speed for less than you'd spend on renting or owning a boat. They're also a lot of fun. If you don't own one, rent one.

Canoeing or kayaking. Outdoor-lovers are active and fit. Find out why by renting a kayak or canoe (a much cheaper option than a speed boat or jet ski) and getting those arm, shoulder, and back muscles into action. If you live near a lake, you can probably find someone who owns a canoe or kayak and is willing to teach you the basics.

All-day barbecue. Load the cooler. Bring the grill. Invite some friends. Don't forget the shade, sunscreen, and drinking water. If it gets too hot, jump in the lake. Bring plenty of toys for the kids. Toss the football around and—since swimming makes even the hardiest dieter hungry—bring plenty of food. You'll find out that you don't need to rent expensive "toys" to have a great time at the lake.

Swimming. Here's an idea: go to the lake and swim. Bring inner tubes, rafts, beach balls, sand toys, and all those other things people bring when they're swimming. You'll of course want to bring some snacks, water, sunscreen, and shade because you'll need to rest from all the swimming fun at some point.

What are you waiting for? Get out there and enjoy the outdoors.