The NCAA Championship (9 p.m., CBS): It’s college basketball’s biggest night of the year

The NCAA Championship (9 p.m., CBS): It’s college basketball’s biggest night of the year as March Madness culminates in April with the final two teams duking it out in San Antonio at the Alamodome. And this time, underdogs need not apply because, as the weekend began, the tournament was down to four No. 1 seeds — a first. So what group of tall guys will be left to cut down the nets and enjoy their one shining moment? As usual, Jim Nantz and Billy Packer provide the play-by-play.

“Yard Crashers” (9 p.m., DIY): Ahmed Hassan goes looking for the perfect weekend warriors.

“Samantha Who?” (9:32 p.m., ABC): “Samantha Who?” returns with its first new episode since December. Poor Samantha is forced to move back into the apartment when she learns that she could be evicted for subletting it to Todd — who has just invited his new girlfriend to move in. Sounds like an episode of “Three’s Company.”

“Nature: What Females Want and Males Do” (2 a.m. Tuesday, PBS): Birds do it. Bees do it. And neither they nor the rest of the animal kingdom (besides humans) need a sex manual or Freudian analysis to get it right. “What Females Want and Males Will Do” is the provocatively titled two-part edition of “Nature” charting some of the techniques that make winners and losers in the animal dating game. Authentic animal magnetism is displayed in Africa, South America and Australia as well as New Orleans and the California desert. Whether it’s drumming, dancing, turning colors or even more exotic techniques, creatures have instinctive courting rituals. This documentary puts them on view.