Do you own the ASUS VG248QE monitor? For a limited time, NVIDIA has made available a G-Sync upgrade kit direct that you can install yourself in about 30 minutes. Once installed, your monitor will be transformed into a smooth gaming G-Sync enabled monitor. It should be noted that the doing the mod will eliminate your VGA and HDMI video inputs, therefore you no longer have audio support. The only display input left working will be DisplayPort. The cost of the upgrade will run you $208.50 shipped.
NVIDIA also has a how-to video up on YouTube that shows how to do the G-Sync upgrade. It is worth watching if you are considering this, so you know what you are getting into. The written installation guide can be found here. Just remember this will void the warranty on your monitor and NVIDIA says they are not responsible for any product damage or warranty issues. If you want a warranty, we highly suggest waiting for the retail monitors to come out.