Now that I think about it, I have these all the time, except it's not things that I don't have time for, it's things that are too ridiculous for novels. (Most end up becoming in-story comic books, video games, etc.) The most recent one was when I saw a copy of "Abraham Lincoln: Vampire Hunter" and thought about how it doesn't make much sense to use Lincoln; it should have been Teddy Roosevelt. The man got shot in the chest during a speech, and then finished the speech. He could totally take on a vampire.
Another one was an expanded universe for "Pere Ubu", crossing over with other things. If you're not familiar with Ubu, he's from an early Absurdist play from the 1900's (or so), inspired by Mr. Punch of the Punch & Judy shows with shades of Gargantua and Pantagruel--in modern pop-culture terms, he's a cross between Peter Griffin and Johnny the Homicidal Maniac. When I was in college, I made a movie in which he battled Dracula and Godzilla (I played all three, as well as Vladimir & Estragon, two video game bosses, Bjork, and R2-D2). Now I'm invisioning a sort of expanded-universe thing, with Ubu combating Disco Rasputin, Cyborg Dracula, super-strong Eva Brawn [sic] and the Brain of Hitler, the League of Public Domain Villains, and so on. If I had the time and know-how, this could be a web-comic, but I just don't think it's ever going to get to that stage. "Ubu Unleashed" will probably wind up an indy comic read by the hipster kids in my currently-paused YA cosmic horror WIP.
And finally, what if a guy with Ausperger's had control of the weather? He'd follow statistics perfectly--if they predicted 70% chance of rain, it would rain 70% of the day.
Everybody loves using things as other things, right? Check out my blog at the Cromulent Bricoleur
and see one hipster's approach to recycling, upcycling, and alterna-cycling (which is a word I just made up).