“So You Think You Can Dance” (8 p.m., Fox): The top 20 dancers selected perform for the

“So You Think You Can Dance” (8 p.m., Fox): The top 20 dancers selected perform for the judges.

“Celebrity Circus” (9:30 p.m., NBC): Under the big top, eager celebrities will show off skills that include performing with “fire knives,” swinging from a trapeze and walking along a tightrope. Jason “Wee-Man” Acuna, Blu Cantrell, Stacey Dash, Janet Evans, Rachel Hunter, Christopher Knight and Antonio Sabato Jr. — coached by circus experts — will attempt their stunts for a live studio audience each week.

“Top Chef” (10 p.m., Bravo): It’s the last supper for the final three chef contestants, who will be cooking their hearts out.

“Men in Trees” (10 p.m., ABC): It’s the final episode. Producers promise to tie up the stories. It all goes out with Elmo’s first talent show.