Guy: Hey bro, what's Obama's last name?
Guy 2: It's...... oh shit.

Person 1: What's Obama's last name?
Person 2: It's Obama
Person 1: So his name is Obama Obama?
Person 2: Yes

The three unsolved mysteries are

Area 51
Bermuda Triangle
And Obama's last name

person 1 "do you know Obama's last name?"
person 2 "ummmmmm"

Idiot: Hey, what's Obama's last name?
Person: Excuse me. did you pass high school?

Person 1: Hey what's Obama's last name?
Person 2: It's "Care"

Guy: hey do you know what’s Obama’s last name is?
Other Guy: nobody knows