Steve Jobs once said that creativity is simply the ability to connect things. He went on to say that creative people have the ability to connect experiences they've had to synthesize new things.
Creating comedy is the exactly the same. Comedy writers connect personal experiences to almost all things and then make a twist or trap door the audience with a punch line creating an entirely new thing.
Funny people possess the ability to set the audience up by seemingly going down a familiar path and then bam!.. corrupt that path into a water slide!
William Plomer said that 'Creativity is the power to connect the seemingly unconnected'.
That makes for a great joke writing exercise....
*Write down 2 unconnected things and then find a connection however slim. Remember to think funny. I'm bettin' you write something hilarious! ;) Let me know how it works for you!