Recently I have been working with a Leap Motion. I surprised me how easy it was to set it up under ubuntu (and windows for that matter), once you know where to get the right files.
A while back linux was not officially supported. However there were some beta drivers available. Luckily now it is much easier. Just go to leapmotion.com/setup and download the linux driver. When you visit the site from a linux machine it probably offers you the right driver right away. Unpack the downloaded archive, install the appropriate .deb via your preferred way, i.e. doubleclick it to open and install it via the Ubuntu software center. After everything is installed (re)connect the Leap Motion. If the green light on the front is lit, the device is connected. When you see a red light in the middle of the device (might be very dim) you can be assured the device is detecting input. To be sure, open the visualizer via a terminal or Alt+F2.