In the episode, a music producer selects Bart, Nelson, Milhouse and Ralph to be members of the next hit boy band, who record songs containing subliminal messages about joining the Navy.
Bart dons a stereotypical Italian disguise and wins the marathon by cheating, but a bird pulls off his fake mustache during the trophy presentation.
He offers Bart a chance to join a boy band he is assembling called Party Posse, including Nelson, Ralph and Milhouse.
Bart accepts the opportunity, and the four boys quickly rise to stardom, secretly using voice-enhancing software developed by NASA to improve their singing abilities.
Party Posse releases a single "Drop Da Bomb" whose accompanying music video includes the strange line "YVAN EHT NIOJ" in its chorus.
Smash sails the carrier to New York City with the band and Homer (who was in the lavatory at the time) still onboard, and declares his intention to destroy the Mad headquarters.
The employees survive unharmed and Smash is arrested; Bart and his friends are disappointed at not having a chance to appear in Mad, but take comfort in reading the planned parody of them.
[1] NSYNC instantly said yes to being asked to guest star, although Justin Timberlake had to record his lines separately from the rest of the band due to a family death.
In its original American broadcast, "New Kids on the Blecch" was viewed by 18.1 million viewers with a 9.7 rating/15 share making it the top rated animated show of the week.
Granted, it's tough to really mock boy bands, as they always bordered on self-parody; the Party Posse tunes sound a lot like the real thing.