Here are some randomly selected joke topics beginning with the letter 'I'
Insurance
Study Reveals That People Without Insurance Die More Often
Intelligent
Beam me up, Scotty. There's no intelligent life down here. - J.T. Kirk
Intelligent
Why are vampires not very intelligent?
Because blood is thicker than water.
Interested
Keep talking. I always yawn when I'm really interested.
Intelligent
Shock me, say something intelligent.
Intelligent
Keep talking, someday you'll say something intelligent.
Insult
Why is a bee like an insult?
Because both carry a sting!
Intelligent
Q: What do an intelligent blonde and a UFO have in common.
A: You often hear about them, but you never see one.
Intelligent
Did you hear about the very intelligent monster?
He was called Frank Einstein.