By MIKE HUGHES
Gannett News Service

Must-see

Two and a Half Men, 8-10 p.m., Channels 12, 7.

In a year when situation comedies have wobbled, we'll have to celebrate partial successes. In ratings, Men, which shows four reruns tonight, is a hit. It is erratic, but it's funny.

The casting is perfect. Jon Cryer, who once hoped for a role on Friends, plays the nervous Alan, with Charlie Sheen as (logically) Charlie, his playboy brother. Holland Taylor is their mother.

When Alan's wife dumped him, he showed up with his son, at Charlie's home. From there, we get lots of comedy about two opposites.

In tonight's first rerun, Charlie is bitter because his brother refuses to name him as Jake's guardian in the event of his parents' deaths. In the second, Denise Richards - Sheen's real-life wife - plays the ex-girlfriend he's trying to lure back. In the third, Charlie tries to get a sick Alan healthy, so they can date sisters.

The night wraps up with a so-so show: Charlie is eager to meet his ex-girlfriend - who has had a sex change and is played by Chris O'Donnell. There are more complications, in a broad and strained episode.

Worth watching

Fear Factor, 8 p.m., Channels 5, 22. To celebrate the fact that it now has the Miss USA pageant, NBC will have six of the contestants - it won't reveal which ones until show time - on Fear Factor. Before appearing live in the pageant, they were taped doing yucky or scary things. Let's just hope NBC doesn't do the presidential debates.

Air Force One (1997), 8-11 p.m., Channels 9, 2. Harrison Ford plays an action-hero president in this solid thriller. His plane has been taken over by Kazakhstani terrorists. He is aboard and fighting back.

The Parkers, 8 p.m., Channel 25. In a well-acted rerun, T meets a young woman who is perfect for him, except that she's HIV-positive.

Dora the Explorer, 8 p.m., Nickelodeon. Here is a prime-time outing for this show, which is aimed at preschoolers but has an odd charm for anyone. Tonight, Dora and Boots go to a fiesta.

Miss USA pageant, 9-11 p.m., Channels 5, 22. Amid the elegance of the Kodak Theatre in Hollywood, we'll watch women compete. That includes one whom we've just seen win $50,000 for doing disgusting or degrading things on Fear Factor.

American Experience: Emma Goldman, 9 p.m., Channels 48, 16 Emma Goldman was only 20 when she embraced the Communist movement. She became known as Red Emma, a passionate speaker, writer and publisher. She's also been immortalized in Warren Beatty's Reds and in the Ragtim movie and musical. Here's a documentary.

CSI: Miami, 10 p.m., Channels 12, 7. In a rerun, a cigar-maker is killed with one of the instruments of his trade.