Just wanted to hip the hounds to a yummy soft drink. It's called Loco, and it comes in five flavors-- raspberry, blackberry, mango, lime and watermelon. Great fruit flavor (from fresh fruit) plus hot chili flavor (apparently from a mix of jalapeno, habanero, and serrano chiles).
The lime is interesting. Great limey taste, with just a touch of heat at the end. (It would make a fabulous margarita.)
The mango is a little weird. Again, a good mango flavor, but somehow it doesn't work so well with the heat. They just don't meld. (Beats me why-- it's a natural combo.)
The blackberry is my least fav. Not much blackberry flavor and not much heat. Wimpy.
I haven't been able to find the watermelon. Bummer.
The raspberry, though, is worth crawling to the ends of the earth for. Fantastic raspberry flavor socks you in the teeth and then, while you're still reeling, the chili flavor kicks in full power. Man... this stuff is great.
I've linked to their website below. In looking for the website, I also found a review by David Rosengarten on foodtv.com. (He likes the blackberry best, but for the exact same reasons I like it least. Go figure.)
I know it's widely available in NYC-area health food stores, but I'm not sure about other places.