Here are some randomly selected joke topics beginning with the letter 'C'
Cake
He's a few currents short of a fruit cake.
Cab drivers
Did you hear about the idiot who thought a taxidermist was someone who stuffs dead cab drivers?
Cafeteria
Bacteria: The rear portion of the cafeteria!
Cafeteria
Did you hear about the idiot who thought that bacteria was the rear of a cafeteria?
Cage
How did you get here? Did someone leave the door of your cage open?
Cake
What did the cookie say to the unhappy cake?
"Hey, what's eating you?"
Caddy
"How should I have played that last shot?" the bad golfer asked his caddy.
"Under an assumed name."
Cabbage
What is green and goes 'boing, boing, boing'?
A spring cabbage.