Add rum and beer and serve over ice with a lemon wedge. Enjoy!
Notes
Mix the lemonade concentrate with club soda or unflavored sparkling water for even more fizz.
Worried about ice diluting your drink too much? Use large round cocktail ice cubes (they melt slower) or freeze lemonade into ice cubes to add to your drink.
This is best served right away before the beer has a chance to go flat. You can mix the lemonade up ahead of time if needed then add the beer and rum just before serving.