Still haven’t figured out what to do with your free time this Memorial Day weekend? Justin Timberlake has the perfect suggestion: Bro-Biking! The film and music star popped up on Instagram on Saturday in what at first looked like an innocent video him of biking through the countryside. Bro-biking. @jimmyfallon ? #memorialdayweekend A post shared by Justin Timberlake (@justintimberlake) on …