The Big Bang Theory Season 4 Episode 16 The Cohabitation Formulation

Leonard is trying to convince Penny to move in with him, but she is hesitant because she doesn't want it to ruin their relationship. Meanwhile, Sheldon is faced with a conundrum when his assistant, Alex, develops a crush on him. He tries to find a way to let her down gently without compromising their working relationship. Raj and Howard decide to try and find a new woman for Raj to date, but their efforts don't go as planned. The group must navigate the ups and downs of their romantic relationships while also dealing with the usual craziness of their daily lives.