The #GiveThem20 campaign is trying to be this year’s version of the Ice Bucket Challenge: Celebrities are doing 20 push-ups or sit-ups to show their support for America’s soldiers, and then challenging their famous friends to do it, too. Stephen Colbert got tagged by John Oliver a few weeks ago, and on Monday, Colbert found an unusual way of completing the challenge. One hint: It involves a bit of old-fashioned movie magic.