Paleo lemonade. Take frozen mixed berries and toss them in a biiiiiig container of water, lemon juice, and a touch of stevia. Let it sit over night, then shake super well.
Iced chai is nice, too.
I've taken to occasionally enjoying Nuun electrolyte tablets in my water (always when I run though or if I'm out in the sun for hours like when we go to the water park)