Thursday, 8-8:30 p.m., CBS
Even the superbrained characters on Big Bang will have trouble making sense of May's awkward cliff-hanger, in which Raj (Kunal Nayyar) and Penny (Kaley Cuoco) woke up together after a drunken night. Things will become even more complicated in season 5 as Penny struggles with lingering feelings for Leonard (Johnny Galecki), while he tries to sustain a bicontinental relationship with Priya (Aarti Mann). ''He might end up with two women and no sex whatsoever,'' Galecki jokes. Sheldon (Jim Parsons) will continue his pleasantly odd relationship with Amy (Mayim Bialik); Howard (Simon Helberg) and Bernadette (Melissa Rauch) will plan their nuptials, though trouble looms. Says exec producer Bill Prady, ''The question is, Which is the greatest problem for Howard: that Bernadette doesn't get along with his mother, or that she does?'' Sept. 22