When the original "Beverly Hills, 90210" signed off almost exactly 13 years ago, it was kind of a big deal in TV terms.The show helped put the fledgling Fox network on the map. It ran for 10 seasons and 194 episodes. It was, for a time, a pop-culture icon.The sequel series 90210 signs off tonight - and it is not a big deal. The only splash this series on The CW made was when original cast members showed up.Yeah, it's been on for five years and 114 episodes, but most Americans have never seen it. Or even heard of it.Nonetheless, it wraps things up with an hourlong retrospective (7 p.m., Ch. 30), followed by the final episode (8 p.m., Ch. 30).Elsewhere on TV ...How I Met Your Mother (7 p.m., CBS/Ch. 2): The gang gets ready for Barney and Robin's wedding - and is it possible that we're finally going to meet the mother in the title?Dancing with the Stars (7 p.m., ABC/Ch. 4): The remaining contestants perform.The Voice (7 p.m., Ch. 5): The top 12 contestants perform.Defiance (7 and 9 p.m., Syfy): Irisa's past comes back to haunt her.2 Broke Girls (8 p.m., CBS/Ch. 2): Caroline and Max make a discovery that could relaunch their cupcake business. (Season finale)Warehouse 13 (8 and 10 p.m., Syfy): Pete and Myka are transported into a crime novel.Mike & Molly (8:30 p.m., CBS/Ch. 2): Molly doesn't realize another teacher is hitting on her.Hawaii Five-0 (9 p.m., CBS/Ch. 2): McGarrett helps his mother with a covert operation.Castle (9 p.m., ABC/Ch. 4): Beckett is forced to reconsider her career and her relationship with Castle. (Season finale)Revolution (9 p.m., NBC/Ch. 5): A drone strike puts everyone in danger.Independent Lens (9 p.m., PBS/Ch. 7): "The Invisible War" reports on rape and sexual assault within the ranks of the U.S. military.The Secret Life of the American Teenager (9 p.m., ABC Family): Ben's obsession with Amy has Leo concerned.Nick News with Linda Ellerbee (9 p.m., Nick): Kids and celebrities talk about "The Top 10 Annoying Things Siblings Do."Bates Motel (11 p.m., A&E): Miss Watson encourages Norman's active imagination.