In all 3 cases, someone forgot to pull it out.
Burning Man.
Your grandparents.
Do you swear to pull the tooth, the whole tooth and nothing but the tooth
I think I could pull it off
3, duh. (My ex's 9 year old little sister told me this joke, and followed is up with: "and YOU'RE the math guy!" >< Burned.)
3, and the rest are true stories.
Kick boxing
Brother-ation I've forgotten your name!
Chen says, "it is because I have forgotten her name"
Some idiot forgot to pull it out in time.
Someone didn't pull it out in time.