Combine water and tea in a medium bowl; cover and steep 2 1/2 minutes. Strain tea mixture through a fine sieve into a bowl, and discard tea leaves. Add mint; steep 5 minutes. Add sugar; stir until sugar dissolves. Cool completely. Serve over ice.
A few leaves of fresh or dried lemon verbena add a lovely citrus flavor. Be sure to use Chinese green tea, such as Gunpowder Green, Young Hyson, or Formosa Oolong.