This upcycle nearly crosses the line because I would never advocate destroying a perfectly good book. You would be much better sharing, selling or giving to a charity shop once finished.
Projects to do on your own
Everyone knows that plastic bags are the root of all evil
We all seem to get more than you could ever reuse, recycling is an option but then again it no where near as much fun or as rewarding as upcycling them into something else that you can use.