Your summer schedule probably includes a lot of camping trips, hikes, and concerts. When you're spending tons of time outdoors, sweating out all of your electrolytes, you must remember to stay hydrated.
A Camelbak is a pretty easy way to do that. Load the two-liter bladder up with water (or whatever liquid you please), strap it on your back, and you're ready to go. This particular model fits up to two liters, as well as tons of storage space for the other things you want to bring along. In fact, last year, I bought one of my own before going to a music festival. It was the middle of July, it was blazing hot, and this portable water fountain was my best friend. Because it's a lot easier to wear a Camelbak than to tote around a plastic water bottle, and it will leave your hands free to throw up in the air when you're rocking out at a show. [Camelbak]