Place tea bags in a large bowl. Pour boiling water over tea bags; steep 10 minutes. Remove and discard tea bags.
Combine sugar, 1/2 cup water, and light-colored corn syrup in a saucepan; bring to a boil over medium-high heat. Remove from heat; let stand 5 minutes. Add sugar mixture and fresh lemon juice to tea; stir to combine. Let cool to room temperature. Pour cooled tea mixture into a 13 x 9-inch baking dish; cover and freeze for at least 6 hours or until firm. Remove tea mixture from freezer; scrape entire mixture with a fork until fluffy. Spoon into a container; cover and freeze for up to 1 month. Garnish with lemon slices and mint sprigs, if desired.