I find my biographical dictionary a great source of fun and inspiration. You can get free online versions, but nothing beats the speed with which you can leap from one paper page to another, from one historic dude to another, making connections here, there and everywhere.
Don't restrict yourself to considering only people you read about in your Biog. Dictionary.. You can make connections from historic people who lived three thousand years ago with people you know, principle participants in a wedding at which you're the Best Man, people in the papers., actors, anyone whose name sparks off any train of thought, leading your mind anywhere.
I find the most success in this and other gag-writing methods is use of: the Three C's.
The Three C's: Compare, Contrast and Connect
My joke on the accompanying web page: 'If Emily what's her name who wrote Wuthering Heights married the legendary financier, George Soros, would she be called Emily Bronte-saurus' is an example of this.
This joke also uses another method, which is to break down names, descriptions, titles etc, moving them here and there and swap them around.
it also deliberately disguises 'Bronte' to make the joke less predictable.
Don't let little things like the physical impossibility of two people marrying if thy couldn't possibly have met get in your way. My main point in the above joke is that there is a link, a connection between Bronte and Soros, combining to generate Bronte-Saurus
Wherever you can make any connection between two or three ideas, concepts, people, there will always be a joke, even if you have to snuffle it out for a while like digging up a truffle.
When I picked up my Biog Dictionary the other day, one of the first people I read about was Archimedes, the great Greek scientist, mathematician and general thinker, but more famous for leaping out of his bath and running naked down Athens High Street shouting Eureka!
One of the first things I did was to halve his name, arriving at Archer and Medes. An instant connection leapt to the forefront of the special part of my brain that generates bad jokes. The connection was people called Archer.
The most obvious was Geoffrey Archer the author. Looking in the Biog. Dictionary led me to Fred Archer, the most successful jockey in Victorian times.
Generally, folks, in a joke you only need three of anything. Yes, it's another joke structure, known as the Rule of Three. The 'An Englishman, an Irishman and a Scotsman went into a pub and...' jokes are great example of this.
So I came up with my three Archers. And Archimedes provides a wonderful punch-line. Here's my joke:
'I can think of three famous Archers: Geoffrey Archer the novelist, Fred Archer a legendary jockey, and Archer-Medes, famous as the first streaker in recorded history.'
After you've been a trainee gag-meister for a while, comic thoughts will leap into your head, as if from nowhere more and more often.. You will steadily be becoming a gag-meister extraordinaire. Enjoy the journey.