Here are some randomly selected joke topics
Stamps
How many 2 cent stamps are there in a dozen?
12
Bankers
Why did the banker decide to break up with his latest girlfriend?
He lost interest.
Tires
If tires hold up cars, what holds up airplanes?
Hijackers.
Exams
Father: Well son, how are your exam results?
Son: They're all under water
Father: What do you mean?
Son: They're all under C level.
Cows
What do you get if you cross a cow and a duck?
Milk and quackers.
Donkeys
How do you get five donkeys on a fire engine?
Two in the front, two in the back, and one on the roof going EE-AW-EE-AW.
The Bell
Knock, knock.
Who's there?
Ammonia
Ammonia who?
Ammonia little girl and I can't reach the bell.
Dumb
Your mumma is so dumb she can't even pass a blood test!
Girlfriends
Last night my girlfriend said that I am a great wit.
Well, she's half right.