Here are some randomly selected joke topics
Knock Knock
Knock, knock.
Who's there?
Justine.
Justine who?
Justine time.
Trees
What do fir trees do when they are sad?
They pine a lot.
Lawyers
Last year a group of terrorists hijacked a planeload of lawyers. They said that they'd release one every hour unless their demands were met.
Police
What do you get when you cross a police officer with an alarm clock?
A crime watch.
Basketball
Why did the basketball court get wet?
The players dribbled all over it.
Camelot
What was Camelot famous for?
Its knight life.
Dogs
What breed of dog is always tired when it is in London?
An English sleep dog.
Pilot
Why did the pilot visit the physiatrist?
Because he was plane crazy.
Cowards
Cowards rule - If that's OK with you