Lyrics:

[Verse] Knock knock knock Yeah it's me again Penny Opening the door Let's begin Three little knocks Can't you see It's Sheldon on a quest for some tea Knock knock knock Penny Open up quick Got a scientific theory I gotta spit My mind's racing Can't you tell I'm the geeky genius Ringing your doorbell [Verse 2] Knock knock knock Penny Can't you see I need your help with my DVD I've got a problem A neurotic dilemma But with your beauty Everything's better