If you had Martin Luther King Jr. Day off, Stephen Colbert hopes you celebrated it the traditional way — "by sleeping in so you, too, could have a dream" — he joked at the beginning of Monday's Late Show. President-elect Donald Trump spent his day canceling a visit to the National African American Museum, Colbert noted, "although I guess in a way that might be good — the last thing we need is Trump learning more about segregation." The big Trump news, of course, comes from his Twitter account.