Tell me if the joke stinks or not:
One day I saw a CIA agent. He seemed pretty cool, so I walked up to talk with him. I asked him, "hey, if you work with the CIA, can you tell me if aliens exist?" Then he said worriedly, "I don't know what you're talking about. What are you talking about? I don't care what you're talking about." Now come on, a CIA agent should at least know SOMETHING.
This is 100% fictional.

It stinks.
You're welcome.

Where's the punch line?

Could it be this one: "a CIA agent should at least know SOMETHING."

...but the joke stinks anyway

Joke is more than slightly lacking in humourous aspects of any type.

It has no punchline also you know CIA agents aren't supposed to reveal they are a part of the CIA.

did you come up with it yourself?

http://www-personal.umich.edu/~kevinpo/art/LAME.jpg

You know a jokes no good when you have to clarify it with:

"This is 100% fictional"

Closed before it becomes a spam thread.