The Hot Troll Deviation (2010)

When the guys run into Howard's ex at the Cheesecake Factory, he ends up confronting his lingering feelings for her. He seeks help from Penny, who agrees on the condition that Howard reveal the reason behind his breakup. He confesses that Bernadette caught him engaging in cybersex with a fellow World of Warcraft player, later revealed to be a male colleague at the university. Howard and Bernadette discuss their relationship at the restaurant and make amends, deciding to give it another try. They go out on a date and are last seen making out in her car.

Meanwhile, Sheldon and Raj are working together and start to argue about whether or not Raj can have his own desk in Sheldon's office. Sheldon cites budgetary reasons and Raj offers to buy his own desk, provided he can also put it in the office. Sheldon arrives at the office later to find Raj sitting behind a large and ornate desk, with its purpose being to annoy Sheldon. He demands it be removed and Raj refuses, leading to an escalating battle of annoyances. Eventually, Sheldon tries to "smoke" Raj out with hydrogen sulfide gas. Raj decides to counter by lighting aromatherapy candles, igniting the gas. Raj and his recently acquired parakeet vacate the office in a cloud of smoke with Raj stating "This is not over."

Note: Melissa Rauch became part of the main cast in this episode. Katee Sackhoff and George Takei guest star as Howard's love gurus.

Title reference: Howard's online affair in World of Warcraft with a female troll.