David Theune

When Howard dresses up as Sheldon for Halloween, Sheldon seeks retaliation at Leonard and Penny’s Halloween party; Meanwhile, Leonard is shocked that Penny doesn't remember their first kiss.

While Raj is worried that people won’t take him seriously in his own field after publishing a paper suggesting he may have discovered alien life, Penny encourages Leonard to stand up for himself when he wants to be the principal investigator on a plasma physics study.

Glenn announces that all employees will receive a $200 bonus if the store reaches a sales goal by the end of the day; Jonah has an encounter with Amy's husband; Dina and Glenn plan a celebration.

When Sheldon is no longer academically challenged at Medford High he audits a college class taught by a professor (special guest star WALLACE SHAWN).

Ron and Alex react very differently to a seemingly selfless patient. Joyce runs into an old flame. Matt helps Bruce find a new best friend.

Ron and Matt try to convince a child to get his shot. Alex helps Joyce with wedding planning. Bruce and Serena butt heads over Matt.