That '70s Show - Season 6 Episode 16 -

When Kitty gives a cocktail-party, the men all dress up because of Jackie's sexy ma Pamela 'Pam' Burkhart, envy Bob who got another good looker after Midge and agree it must be a matter of money more then charm, while their daughters agree that mismatch may not go trough but are ignored. The doctor gives Red a heart monitor, but Kitty uses it as a lie-detector to trap him till it is proven to react to... Simple hedonist Kelso is the only one who uses Bob's hot-tub after the odd couple, au naturel, so his scumbag 'mates'...