TONIGHT'S MUST-SEES

"Two and a Half Men," 8 p.m., CBS. A fine experiment begins. This episode was written by "CSI" people, complete with a murder probe. Thursday's "CSI" was by "Two and a Half Men" people, with a slain sitcom star. This could be fun.

"American Experience: George H.W. Bush," 9 p.m., PBS; concludes tomorrow. The senior George Bush became all the things Ronald Reagan pretended to be, this affectionate documentary says. Reagan portrayed athletes, war heroes, family men. Bush was all of those in real life. In part, he was like his own father, who chose principle over politics; in part, he strayed. A moderate, he courted the extreme right. At various points, he vowed to oppose a civil rights bill and any new taxes. Ultimately, he broke both vows. He was a fascinating study in opposites.

OF NOTE

"Gracie's Choice" (2004), 6 p.m., Lifetime. Before getting their own shows, two actresses were superb in this true-story movie. Anne Heche is a shabby mom; Kristen Bell is a teen, determined to keep her family together.

"Big Bang Theory," 7 p.m., CBS. Who knew that Sheldon has a hot-looking twin sister? He does, apparently, and his friends get excited. That may sound corny, but this series has been extraordinarily funny.

"Bones," 7 p.m., Fox. Brennan battles all her friends and colleagues. Her father (Ryan O'Neal) is on trial for murder and all of them are witnesses. That leaves only Brennan to help the defense.

"House," 8 p.m., Fox. One of House's obsessions has been a silly medical soap opera. While watching it, he suspects the star is unaware of a health crisis. Meanwhile, House is also happy that Wilson has finally had a fight with his girlfriend Amber.

"Medium," 9 p.m., NBC. Allison has visions of a charming and ruthless killer. In real life, however, the same man is severely impaired, with a bullet in his brain.