One thing you've got to ask yourself if you're writing something with a comic edge is what exactly is funny. As anyone who's ever listened to a long winded joke in a pub knows, it's very easy to get wrong. More to the point, how do you make comedy work best when you're writing? Is it about essentially ludicrous characters, silly situations, and jokey plots?
On the whole, I'd like to think not. Exagerated characters and plots certainly have their place, but they are central to the basic story that you're telling. Mess with them, and you run the risk of the whole thing falling flat to get a laugh. My short story 'A Madder Scientist' (click on the link to Semaphore Magazine now, or I'll cry) comes pretty close to doing this, but it's A: quite a short short-story, so it doesn't really have room to go wrong in that way, B: essentially a parody, and C: in complete possession of a fairly normal plot somewhere under there (i.e. "the nephew who must go into the family business for an inheritance while others try to steal it." It's a hoary old chestnut, but is quite fun when the business in question is Mad Scientist) even if the details are all silly.
I think that's maybe the point here. Start with something normal, something that, if stated in general terms, sounds sensible. Only then branch out into the ludicrous.