There have been important season finales for How I Met Your Mother over the years, but it is really hard to imagine any being as significant as what we are about to see coming up for the show’s all-important eighth season. After all, the show bosses Craig Thomas and Carter Bays have already confirmed that Barney and Robin are actually going to get married by the end of the season,and this means that we will finally be at the moment when Ted meets the famous mother.
So when will this air? According to CBS, the end of How I Met Your Mother for the spring will be on Monday, May 13, though there is no official word yet as to whether or not it will be a one-hour or 30-minute episode. What is most important is merely that the wedding will be taking place to close off the season pending some big surprise where it happens early, though we do know already that episode 21 is set to feature Barney’s bachelor party. (Source)