Cinema's Secret Influence?

Three great movie scenes from the past ten years:

1) Kevin Spacey sings along with "American Woman" in American Beauty.

2) Philip Seymour Hoffman as Lester Bangs in Almost Famous ... his scene starts 2:28 in, and the below quote starts at 3:03. If you don't have the patience to wait for the clip to load that far, he says:

"The Doors? Jim Morrison? He's a drunken buffoon posing as a poet. Give me The Guess Who. C'mon - they got the courage to be drunken buffoons. Which makes them poetic."

3) Micheal Cera (he's Canadian!) sings "These Eyes" in Superbad.