Cheryl

Cheryl was a colleague of Penny's at the Cheesecake Factory.

She attended Penny's Halloween party, in The Middle Earth Paradigm, and bumped into Raj after having a couple of drinks. She proceeded to ask him "How wasted am I?" Raj did not answer because of his selective mutism. Later that night, Cheryl had sex with Raj, praising him for being such a good listener.

In The Pancake Batter Anomaly, Cheryl was seen again working at the Cheesecake Factory when a sick Sheldon appeared; she warned Penny about the "homeless crazy guy at table 18" to which Penny answered, "no... just crazy".