Season 4, Episode 4 began with the best Barney antics, nay the best antics of any show period.  Barney used an old man outfit combined with the concept of time travel to get laid!  It was pure brilliance and pure laugh out loud comedy.  The rest of the episode focused on a series of interventions.  The first of which was for their friend Stuart for his alcoholism.  After this serious intervention, the gang decides to use the concept anytime they didn't like something about one of their friends.

Whether it was Marshall's "cat in the hat" hat, Lily's fake English accent, or Barney's magic trick, they all got some funny interventions.  However, when Ted finds the remains of an intervention the gang planned for his marrying Stella, things get serious.  The whole gang realizes they're not ready for change.  Ted for marriage, Marshall and Lily to move into their new place, and Robin isn't ready to move to Japan.  Oh and Barney isn't willing to give up macking 22 year olds, which he tries to prove by picking up a 22 year old as an 83 year old man.  And it works!

In the end of the episode they all agree to go on with their lives but to meet in one year at McLaren's and buy the $2400 bottle of Scotch to celebrate.  All in all it was a fantastic episode.