"So You Think You Can Dance," 8 p.m. KMPH (Channel 26.1): The weeks of auditions are over and the Top 20 contestants have been selected. Tonight's special of "So You Think You Can Dance" will feature the dancers competing as couples. Two finalists will be eliminated in a two-hour performance show that will be broadcast Tuesday. The top girls include Channing Cooke, Ariana Debose, Ashleigh Di Lello, Mollee Gray, Karen Hauer, Noelle Marsh, Pauline Mata, Kathryn McCormick, Bianca Revels and Ellenore Scott. The top guys are Phillip Attmore, Billy Bell, Ryan Di Lello, Russell Ferguson, Kevin Hunte, Jakob Karr, Legacy Perez, Peter Sabasino, Victor Smalley and Nathan Trasoras. Nigel Lythgoe, the scary Mary Murphy and Adam Shankman will pick who keeps dancing and who goes home.