Barney goes missing for 2 months with Homer's car.
This is a classic episode with great humour, character moments and artwork.
The set up involving a massive drinking session at Moe's, with a certain designated driver, is hilarious and leads perfectly to a Simpson family jaunt to NYC.
Everything that happens in NY is highly enjoyable, particularly Homer's ordeal that is nicely contrasted by the sightseeing trip of the others. It all builds to the fantastic moment when they meet up together at the end.
The animators deserve a huge amount of credit for the quality of this episode as they not only bring NY to life but produce a tremendous amount of the humour visually. It's all just enhanced by the voice performances, sound effects and music.
For me it's a 9.5/10, but I round upwards.