"I don't know" - Timmy talking to Dwight about the kind of wood the rocking chair in his room was made of.
Timmy Wallace is the son of David Wallace, he is skilled at drum playing and claims the chair in his room was there when he was born.
Timmy was first seen in the episode Cocktails. He was asleep in his room during a hosted party. He awoke to find Dwight sitting in the rocking chair in his room. Dwight became frustrated with the boy for not knowing what the chair in his room was made of by asking, "What do you know?" mocking the boys constant response of "I don't know".
His most recent appearance was in the Season 6 episode, Sabre. When Michael went to go visit David, he saw Timmy playing the drums in the living room. At the end of the episode he was playing the drums while his father sang about his newest invention, Suck it.