CBS

Season 9: Episode 17 - Rally

Rally: As Barney and Robin's wedding day dawns, the groom (after an epic night) is not exactly in marrying shape. The gang can think of only one way to get Barney to rally from his worst hangover ever...but it's not gonna be easy. Lily and Robin attempt to slap/scare Barney awake while Marshall and Ted get the far-fetched ingredients necessary for the Stinson Hangover Fixer Elixir, all in time for the pre-wedding photo shoot in two hours.