Matt, were the pop rocks kind of stuck together before you added the liquid? Because sometimes with things that old you have to smash them up while they’re still dry to avoid getting hard globs. I wish I could tell you I learned that from Gourmet magazine rather than by drinking any old crap I find in the cupboards. And, on that note:

Crystal Light Lemon-Lime is pretty darned good. Of course, the cannister I was drinking it from was ten years old, and that was five years ago, so maybe now it’s just crappy like their "shake your bottle" commercials. But, if not, it’s a pretty good drink to knock back after you’ve been mowing the lawn.