Jay Leno is hosting The Tonight Show (10:35 p.m., NBC/Ch. 5) for the last time, and this time it might actually be true. I can't really see him taking the show back again, not with Jimmy Fallon taking over on Feb. 17.Leno's last guest are Billy Crystal and Garth Brooks. And it will be fascinating to see how he handles his farewell.Elsewhere on TV ...The Big Bang Theory (7 p.m., CBS/Ch. 2): Sheldon, Amy, Howard and Bernadette take a trip together.The Taste (7 p.m., ABC/Ch. 4): The cooks create deserts.American Idol (7 p.m. Fox/Ch. 13): The Hollywood Round of the competition begins.The Vampire Diaries (7 p.m., CW/Ch. 30): There's a dance for broken-hearted students.Under the Gunn (7 and 11 p.m., Lifetime): The contestants create vampire-inspired looks.Men's college basketball: Washington at Utah (7 p.m., P12N); Santa Clara at BYU (9 p.m., ESPNU)The Millers (7:30 pm., CBS/Ch. 2): Nathan is determined to surprise Carol on her birthday.The Crazy Ones (8 p.m., CBS/Ch. 2): Simon is asked to give the eulogy for a guy nobody liked.Rake (8 p.m., Fox/Ch. 13): A gambling addict defrauds and insurance company.Reign (8 p.m., CW/Ch. 30): Queen Catherine is accused of adultery.Two and a Half Men (8:30 p.m., CBS/Ch. 2): Alan learns that Lyndsey broke up with Larry.Elementary (9 p.m., CBS/Ch. 2): A ballerina is murdered.