Here are a couple of Pivy scripts that might be handy. They are used with the SoPyScript node in Open Inventor or VRML files.

• EventListener - a simple script that outputs the mouse position and button states received via the SoHandleEventAction as fields. Handy for scripting with mouse input.
• Navigation - a walkthrough navigation style using a 2D input vector. It implements intersection detection for staying a fixed height above the ground and not allowing you to walk through walls. The intersection geometry is parameter of the script node.