What makes classic root beer float special is caramel syrup. You can vary ingredient combinations as you prefer: Try orange soda, or chocolate ice cream topped with chocolate syrup.
Spoon 1/2 cup ice cream into each of 8 (12-ounce) glasses. Pour 3/4 cup root beer over ice cream in each glass. Drizzle each serving with 1 tablespoon syrup. Serve immediately.