The boys and girls at comedy site Something Awful have written stories by "famous writers as children." The exercise starts with a sharp send-up of Chuck Palahniuk, discussing the love of humans for helpless puppies (a topic so close to us all this week). In the example below, David Foster Wallace (age 10) writes to his parents asking for a bigger allowance.
OK, so bearing in mind the fact that I have spent a pretty-considerable amount of time in what I consider "good" behavior (although by "good" I'm assuming you already have a pretty good handle on most of the ethical philosophies of like all post-19th C. philosophers— although Hume probably isn't so pertinent; I'll leave this up to you) (By the way, this is probably also a good time to mention that my sinistral phalangeal joint is a little askew due to an unfortunate playground-slide mishap — any dodgy penmanship or unavoidable typos sic), that is to say, not punching my sister or politely asking for more juice instead of just promoting it under stealthy cover of night-time pajama-raid, &c. &c. you may be wondering just what exactly it is I'm up to, like do I have an ulterior motive or whatever.
The rest of Wallace, with footnotes, is here. Other good ones: Terry Pratchett, Ernest Hemingway, and Jane Austen.