1 Quart water
1 Cup sugar
1 Cup FRESH lemon juice
Sparkling Water (not tonic water, like Perrier)
Mix first three together. Fill a tall glass 2/3 to 3/4 with lemon mixture then fill with sparkling water.
An interesting variation is to puree some fruit (raspberries, strawberries, etc) with a little superfine or powdered sugar and put that in the glass before adding the the lemonade and water.