I'm sure a million other people have thought of this, but it's sort of new to my brain.
Next time you have iced tea, instead of using ice, use frozen fruit! You know, those strawberries you've been freezing for smoothies? I put a few whole, frozen strawberries in my iced tea today. (It's peach flavored from Crystal Light. I never buy diet stuff but had this at a friend's and really liked it!)
As the fruit thaws, it actually adds extra flavor to the iced tea. Then, when I was about halfway down the glass, I put it in my Magic Bullet and made a strawberry iced tea smoothie! Yummy sweetness with very, very few calories!