Place the tea bags in a very large mug or other heatproof cup. Pour boiling water over teabags. Brew tea for about 5 minutes (should be dark and bitter at this point). Remove tea bags, squeezing with a spoon to remove the liquid. Stir in sugar until dissolved.
While tea is brewing, fill shaker and a glass or two with ice cubes. Pour hot tea over ice in shaker until almost full (be careful-the shaker will get quite hot for a moment!). Replace lid and shake until cold; strain over ice in glass. Add remaining tea (and additional ice, if needed) and shake until cold.