A vibrant sweet tart of a drink made with fresh prickly pears, frozen raspberries, and lime. Along with being economical, frozen raspberries add an extra bit of chill to the drink (not to mention they're a bit more flavorful this time of year) but if you'd prefer to use fresh they would work well too. Agua can be made and kept cold for up to 4 days. Keep covered and make sure you stir before serving.