"The only thing phony and insincere on this show is me." So says Paul Reubens, who plays the oily host Troy Stevens on "You Don't Know Jack" (8 and 8:30 p.m. ABC), a new quiz show based on the popular CD-ROM game.
The first half-hour is not entertaining, but there's one unexpected bit involving mariachis who distract the three contestants competing for cash. Aside from that, in the world of prime-time game shows, it is the weakest link. Goodbye.
This evening's other noteworthy PBS program is the season finale of "American High" (10 p.m. KCET, KVCR), R.J. Cutler's well-received documentary following high school students who keep "video diaries" of their lives in Illinois. Fittingly, the program deals with graduation and plans for the future. One of the teens fouls up at the last minute and misses his commencement; another laments the lack of communication with her father.
"South Park" (10 p.m. Comedy Central) kicks off its fifth season, serving as a lead-in for "Primetime Glick," a new Martin Short comedy premiering at 10:30 p.m.
Shawn and Marlon Wayans host "Teen Choice Presents: Teenapalooza" (8 p.m. Fox), a variety show featuring performances by Mandy Moore ("In My Pocket"), Sisqo ("Can I Live"), Shaggy ("Angel") and Eden's Crush ("Get Over Yourself"). Feel free to pass if you're over 18.