Portland Design Works sales doof Kevin Murphy, known to much of the world as Murph (a man who looks and behaves like a Jackie Gleason muppet on ether), wrote this morning to remind us of PDW's new mud guard for fat bikes, Dave's Mud Shovel.  The accompanying video illustrates in vivid color how amazingly, even effortlessly, this fender sheds overspray thrown up by 4" tires even in deep mud holes (it seems like a Luby's mom joke should go here).  My mind was blown. Dave's Mud Shovels from PDW on Vimeo. The Dave of Dave's Mud Shovel fame is none other…