I assume, if you bother to visit my wee corner of the web, that you're a Neil Gaiman fan, as the awesomeness of Neil Gaiman is one of the few things geeks as a whole agree upon. If you've never heard him reading one of his own stories, you can get A Study in Emerald for free from Audible.com. It's a wonderful Holmes-ian story that clocks in at just under 45 minutes.
By the way, I feel obligated to say that this isn't a product placement or referral link for which I get a kickback. It's just awesome and free, and when I found it while browsing Audible, I thought other folks might like it.