The Ballad of Lon Sarofsky - S3.E20

The gang is shocked when Penny rebounds from her breakup with Pete by having a torrid affair with the last man on earth they'd pick for her -- the Car Czar. To make matters worse, she's temporarily living with Brad and Jane, who end up acting like disapproving parents. Meanwhile the friends pressure Max to get a job so he'll stop sponging off them.