You guys seemed pretty excited when I shared a simple tip to keep your iced coffee from getting watered down . Well, if you thought that one was good, here's one that the folks at Seattle's Best Coffee  emailed to me. Instead of brewing their coffee like normal, they cold brew it overnight, resulting in an iced coffee that can stay fresh for up to seven days.
So what is cold brewing? It's essentially letting coffee grounds soak in room temperature overnight. You'll need a cold brew concentrator , or you could rig one up yourself with some jars and filters. If you're not interested in going the diy  route, the Toddy Maker Cold Brew Coffee System  is available for $28.
And if cold brew sounds too complicated (although it looks really quite simple), you can always brew up a batch of coffee, bring it to room temperature and then refrigerate to use the next day.
If you'd like to learn more about cold brewing, here's a step by step tutorial .