Both an event and a guaranteed anticlimax, the two-hour finale of “American Idol” (7 p.m., Fox) pits Toledo’s Crystal Bowersox against Chicago’s Lee DeWyze.

Bowersox had been the judge’s darling and clear favorite until last week, when they all seemed to fall in love with Lee. Are they genuinely smitten or just playing games to keep it interesting? Adam Lambert, last year’s clear favorite and eventual runner-up, anointed Crystal as the clear favorite. Is that a blessing or a curse?

You have to root for Crystal if only for the fact that her name has to be the least show-bizzy moniker of all time. At the same time, you have to admire Lee for charging from the back of the pack right to the finish line. And besides, his last job was mixing paint at a hardware store, just like Tony Manero (John Travolta) in “Saturday Night Fever.”

As they do every year, the judges want a finalist who is ready to record a hit song and become a pop star right away. But it’s in the hands of the voters, who are capable of surprises.

I’ve long suspected that the average “Idol” voter is a female in seventh or eighth grade. And given the rapturous reception for the spectacularly nonthreatening tweeny-bopper Justin Bieber on last week’s show, I’m sticking to that theory.

There’s nothing new here. The same demographic turned into Bobby Sox rioters for Frank Sinatra in 1943, erupted in Beatlemania in 1964, loved the Gloved One in 1984, and went nuts for the Spice Girls a dozen years back. Girls just wanna have fun.

Is Crystal a model of empowerment to middle-school girls, or does her urban-busker, dreadlocked, single-mother image intimidate them? Lee is not unlike some former winners and contestants. But is he dreamy enough?

Tonight marks the final night of Simon Cowell’s tenure on the show, and one wonders how the series will do without him. For all of the nonsense about him being “mean,” he was frequently the voice of reason. In a popular culture where boosting self-esteem is often seen as an end in itself, Simon’s brutal honesty was refreshing and entertaining.

l Like the best documentaries, “Saving Africa’s Witch Children” (7 p.m., HBO2) takes you to a place you’ve probably never heard of and explores a subject you could not have imagined.

Akwa Ibom State in southeastern Nigeria has long been a Christian region, but recently an extreme strain of Pentecostalism has mixed with indigenous beliefs to create a hysterical fear of witchcraft that far surpasses anything that happened in Salem in the 17th century.

Children by the tens of thousands have been accused of being wizards and witches and have been beaten, burned, executed and abandoned by their families. A thriving racket of priests and exorcists has emerged. It’s easy for a priest to declare a child a witch and then charge the family a fortune to cleanse the child’s spirit. “Saving” follows volunteers and activists who have set up homes and orphanages for the vulnerable and outcast.

Tonight’s finales

• A killer (Tim Curry) stalks Los Angeles on “Criminal Minds” (8 p.m., CBS).

• Danny can’t escape trouble, even on vacation, on “CSI: NY” (9 p.m., CBS).

Tonight’s other highlights

• Shia LaBeouf stars in the 2007 special-effects adventure “Transformers” (7 p.m., ABC).

• “Ground War” concludes on PBS with “Firepower” (8 p.m.) and “Command and Control” (9 p.m., check local listings).