Recruiting Cass usually requires high skill checks, but the highest one (Barter 75) has the best pay off in sheer hilarity. You challenge your team's resident http://tvtropes.org/pmwiki/pmwiki.php/Main/TheAlcoholic to a drinking contest. Depending on your character's Endurance stat, you get wildly different dialogue (this section in fact has the most dialogue options and voiced acting from one dialogue tree choice in the game). Beating her with 10 Endurance is freaking hilarious as she's bested http://tvtropes.org/pmwiki/pmwiki.php/Main/BeyondTheImpossible Cass: Enough! All fi- fou- ... ALL OF YOU! [censored]. I'm [censored]in' wasted and you're just sitting there.
If you tie her in the bout, there's a bunch of different options.
The Courier: I love you and your little hat. Cass: Aww, ain't that sweet. http://tvtropes.org/pmwiki/pmwiki.php/Main/InVinoVeritas: The Courier: Mmmmmwhen ah firsmet you, ahmm thought you werem the mmmbiggestmm mm[censored] in the world.