A low-flow toilet kit, or a dual flush toilet are great ways to reduce your water consumption, but here's another toilet mod that will help you save some water, and give your guests something to talk about.  The Toilet Lid Sink takes water that would normally go straight down into your toilet and first routes it through the sink spout at the top so you can wash your hands after you flush.  That may sound gross, but let me clarify.  When you flush the toilet, the waste goes down the drain and then the clean water from your reservoir tank refills the bowl.  With the sink add-on, the clean water from the reservoir first goes through the sink and then goes down into the bowl.  This extra step won't reduce the amount of water your toilet is flushing but it will allow you to use that water twice, cutting out the use of your sink all together after taking care of business.