Make: Magazine runs a Maker Share site and they are currently partnering with Sigma (the consortium that controls the Z-Wave) to run a Maker Challenge.
Post your idea and if it is selected you will get a kit (Pi with a Z-Wave dongle) and get in the running for a trip to CES in Las Vegas, Nevada.
A quick read of the rules indicates that the contest is not limited to the U.S., though all entries must be in English.
I’m certain we have several people on the forum who can come up with some great ideas on ways to use Z-Wave to solve some problems.