I looked really dweeby - but this worked really well! I carried 2 stretchy trash bags in my backpack - they were the white Glad Force Flex kind. One I put my backpack in for the ride. The other, I tore 2 tiny holes in the top corners, and one slightly bigger hole in the top center (really the bottom of the bag, I uppose...). I put my arms through the side holes (the holes stretched to fit - so I was sealed in!), then my head through the center hole, and then after I sat down, I stretched the thing over my knees (and of course - over my behind!), and then tied the drawstrings. From the knees down, and my arms got wet, but everything covered by the bag was completely dry! Also - the bad weighs NOTHING in your backpack, and you can rip it off and throw it away when you're done riding!