Beer Brewed and Fermented in a Pumpkin!
Sure, why not.
If you haven't seen it, here is a Flikr photo essay of a guy who mashes a beer in a big pumpkin then ferments in another pumpkin. Pretty ingenious, really. He cuts the big pumpkin mash tun up and even puts a copper manifold inside. He then gets another pumpkin and ferments his beer in the thing complete with airlock attached.
Is is Sanitary to Ferment in Pumpkin Guts?
Of course not ... but what the hell, it's just for fun. I've always contended that you could brew a pretty passable
'pumpkin' beer without the least bit of pumpkin due to the fact that what you're really looking for in these beers is the clove, cinnamon, allspice type of flavor.
Watermelon, however, is a different story and I fully intend to brew up a wheat in a watermelon (or two) next summer if I can come up with a way to scrape the guts out.
Here's the full link : http://www.flickr.com/photos/cog_nate/sets/72157602400060222/detail/