After being overwhelmed with bartending, and a call from Carl telling them he is returning, Ted and Barney direct the band upstairs to their apartment to continue partying.
Marshall gets Robin to drive him to the airport in the midst of the snow storm to pick up Lily, arguing with her about the importance of traditions in relationships.
Marshall ignored the call because he felt that all of their traditions were slipping away and that it was a natural progression of their relationship to let their rituals die, from the lunchtime phone-call to the New Year's kiss.
Suddenly, airport residents, the "Fighting Hens", start playing marching band instruments to the tune of "Auld Lang Syne", and Marshall greets Lily.
They joyfully reunite with a late New Year's kiss and Marshall asks if he now has to bring a marching band each time he picks up Lily.