Katadyn MyBottle Purifier White Splash ($35)
Hundreds of people use the water fountain at the gym every day. Some people spit in there, use it as a receptacle for their ABC gum, and who knows the exact number of mouths that slobber on the spout. Avoid germs and drink high-quality H20 with the only EPA-registered bottle purification system on the market. Use any fresh water source — faucet, lake, aquarium — and the filter will rid your liquid of all viruses and bacteria.