If you're sick of having to clean and lube your drive train after every muddy ride and find regular mudguards impractical, this DIY chainset mudguard might solve your problem.
Reader Cam over at Bike Hacks put together a great solution to muddy rides -- a DIY chainset mudguard designed to help keep mud from getting on the chain and then being carried around into the drive mechanism. He's built his out of the top of an old chocolate container, but it looks like any plastic top of the right size would work for you.
Hit up the post at Bike Hacks to see the whole build process.
DIY Chainset Mudguard [Bike Hacks]