Rather than go to McLaren's, their usual hangout, Barney convinces Ted to go to the airport with him to "pick someone up". It turns out that they're there to pick up some girls. While doing this, they fly to Philadelphia, get arrested by airport security and that's when Ted starts to wonder why he ends up in these adventures with Barney. Meanwhile Marshall has studying to do, so Lily and Robin do a girls night out and Lily notices guys are buying drinks and try talking to Robin, so Lily starts to wonder what it would be like to have her engagement ring off, and with Marshall's "blessing", she takes it off. In the end, Lily realizes that things aren't all that great with the ring off and Ted understands why he goes on these adventures/misadventures with Barney.
Did you know?
The plane shown taking Ted and Barney to Philadelphia is a 747, but the inside is of a much smaller aircraft. Also, no airline would use such a large aircraft for such a short route.
Barney: Ted you keep going to the same bar, you're in a rut.
Ted: It's not a rut, its a routine, and i like it
Barney: Ted what's the first syllable in rut-tine?
Ted: [Gives up and gets in the cab]
Barney: Peace out suckers!
Barney: Now, Ted, you can either put the bags on the carousel, or you can wait and listen to me give you a really long speech convincing you to put the bags on the carousel.
[Ted doesn't move]
Barney: ...Ted, since the dawn of time, Man has struggled...
[Ted takes the bags and puts them on the carousel]