TONIGHT'S MIGHT-SEES

"The Simpsons," 8 p.m., Fox. The annual "Treehouse of Horror" tends to be a delight. These are just Halloween-time stories; anything can happen, without altering characters. And the result this year? Well, there's a very funny little opener, in which a machine diverts Homer's votes. After that, things slump off. One sketch has Homer hired to kill celebrities; another has giant Transformers taking control. Both are so-so, at best. The third, however, is a good Charlie Brown parody. The Great Pumpkin does show up — with unexpected results.

"Masterpiece: The Last Enemy," 8 p.m., PBS. This taut thriller wraps up. The security-obsessed government wants everyone tagged. Meanwhile, immigrants face sudden, inexplicable deaths. What's the connection? We find out in a smart (if semi-satisfying) conclusion.

OF NOTE

"Titanic" (1997), 11 a.m., TNT, or "Close Encounters of the Third Kind" (1977), 5 p.m., AMC. Two great movies collide. Gifted directors (James Cameron, Steve Spielberg) knew how to blend stunning visuals with warm human details.

"Primeval," 2 p.m., BBC America (Oceanic Digital Channel 341). Here's a quick rerun of yesterday's season finale. Nick and colleagues are captive and need a plan.

"Brotherhood," 6 p.m., Showtime. The season opens with lives in chaos. Tommy, the politician, hates his errand-boy duties. His brother Michael, the crook, has some brain damage and missing memories. "Brotherhood" continues to be well-made, but has sunk into deep wells of despair.

"Desperate Housewives," 8 p.m., ABC. Having broken up with her young lover, Susan plans to surprise him — with unexpected results. Meanwhile, Lynette suspects Tom is cheating; Gabrielle suspects an offer from Carlos' client is shaky.

"Brothers and Sisters," 9 p.m., ABC. Nora is determined to meet the boy fathered by her late husband — and to do it quickly before Holly steps in.