Fairy tales used to be so simple. Stories for children began with “Once upon a time…” and generally concerned kings and princesses and ogres and trolls. Real basic stuff.

Now many cartoons aimed at kids involve whole pantheons of mystical entities and levels of martial-arts power. You almost have to immerse yourself in an alternative religion to get the gist. Take “Avatar: The Last Airbender” (6 p.m., Nickelodeon).

For starters, what in the heck is an Airbender?

After this debut, “Avatar: The Last Airbender” will air on Friday nights at 7 p.m. on Nickelodeon.

• “Ego Trip’s Race-o-Rama” (8 p.m., VH1) looks at the role of race in movies, music and videos over three nights. Along the way, it continues to exploit and popularize images and ideas that have been kicking around since the time of the first minstrel shows.

Tonight’s presentation, “Dude, Where’s My Ghetto Pass?” looks at ways that whites copy black language, style and slang. Several talking heads explain that if white kids come to their ‘hoods trying to “pass,” they deserve to be beaten up. Then, without apparent irony, Tuesday’s installment, “Blackophobia,” asks, “How much longer will black people be stereotyped as the toughest and most intimidating minority in America?” Probably as long as big corporations like Viacom perpetrate shows like “Dude, Where’s My Ghetto Pass?”

• “American Experience” (8 p.m., PBS) repeats “Malcolm X: Make It Plain” on the anniversary of his assassination.

Tonight’s other highlights

• The top 12 men perform on “American Idol” (7 p.m., Fox).
• Ed calls on an old pal (Sylvester Stallone) on “Las Vegas” (8 p.m., NBC). Gee, I wonder if this has anything to do with Sly’s new NBC reality series?
• Audrey begins to suspect her ex on “24” (8 p.m., Fox).
• A woman seeks legal help to prevent someone from her past from stalking her in the 2005 thriller “Fatal Reunion” (8 p.m., Lifetime).
• Where there’s smoke there’s suspicion on “CSI: Miami” (8:30 p.m., CBS).
• Allison’s brother shares her gift on “Medium” (9 p.m., NBC).