"What is your IQ?" joke

Bob is throwing a party. Bob decides that to break the ice at his party, he'll ask everyone what their IQ is, and then strike up an appropriate conversation from there.
The day of Bob's party rolls around and when the first guest knocks on the door, Bob asks the person what their IQ is.
"200,000," replies the first guest.
"Well, that's great," says Bob, "Let's talk about etherial astro physics." Bob and this first guest talk about the aforementioned subject for a while. Later in the party someone else is at the door.
"Hi my name is Bob. Welcome to my party, what's your IQ?"
The new guest responds with 250.
"Great," says Bob, "Let's talk about advanced math." Bob and his new guest talk about calculus and statistics for a while.
Much later in the party after many more guests had arrived and spoken to by Bob, yet another guest arives at the door.
"Hi my name's Bob. Welcome to my party, what's your IQ?"
This time the guest replies after putting some thought into it: 5.
"Well that's great," says Bob, "What kind of drumsticks do you use?"