18. "Slutty Pumpkin," How I Met Your Mother
Air Date: 10/24/05
Ted (Josh Radnor) would be the type of simp who attends the same lame Halloween party years after meeting a great girl there but losing her number, clinging to the hope that she just might attend again too. Even though cell phones have largely rendered that particular struggle moot, we can all relate to missing out on the most intriguing girl in the spot, even if we wouldn't quite resort to Ted's extreme measures to find her again.
In addition to various recurring gags involving Marshall (Jason Segel) and Lily's (Alyson Hannigan) pirate-and-parrot couple's costume, we're also treated to Barney's (Neil Patrick Harris) genius method for receiving second (and third) chances to bag the hottest chick at the party after striking out the first time: multiple costume changes.