Every time I stop at our local convenience store with the kids, they whine and bitch about getting an "ICEE" or a squishee, or whatever the hell brand it is (not a Slurpee) - they're usually fluorescent blue or red in color, and taste of sugar syrup and dye. If I'm feeling weak-willed, I'll let them get a small cup filled half-way, and figure they'll be good and wired for about 4-6 hours.
