From the brilliant and twisted mind of the infamous John Scalzi, Redshirts is no mere fan fiction or send up, but a clever guise for metaphysical speculation that will keep your head spinning (if you want to think about it that much).
And just when you think your done with the book, there are three more "Codas" to go. The second coda seems to ramble on a bit, but it really pays off in emotional and intellectual satisfaction by the time you're through them all.
You don't have to be a fan of Star Trek to enjoy the hell out of Redshirts (though it sure doesn't hurt ;). Highly recommended.