What was the audition on American idol where judges hid under table?

You're likely thinking about the audition of William Hung on American Idol season 3.

While the judges didn't technically hide under the table, they did sit behind the judges' table with their heads down in apparent embarrassment and disbelief as Hung performed a rendition of "She Bangs" by Ricky Martin.

The moment became an instant viral sensation and helped to catapult Hung into a brief period of fame.