Here are some randomly selected joke topics beginning with the letter 'L'
Leave
If I throw a stick, will you leave?
Leave
I'd like to leave you with one thought...but I'm not sure you have anywhere to put it!
Leave you alone
Knock, knock.
Who's there?
Waddle.
Waddle who?
Waddle you give me if I leave you alone?
Leeks
What type of vegetables do plumbers fix?
Leeks.
Learner
I don't have a license to kill. I have a learner's permit.
Leave a message
So long as phones can ring and eyes can see,
So leave a message, and I'll get back to thee.