The Panda3D Distribution includes quite a few sample programs. The following is a list of what's included, and which features of the engine each sample demonstrates. If you are just learning Panda3D, take a look at the ones marked as "Beginner" difficulty.
To run a sample program, you need to install Panda3D. If you're a Windows user, you'll find the sample programs in your Start Menu. If you're a Linux user, you'll find the sample programs in /usr/share/panda3d. On Mac OS X, you'll find them in /Developer/Examples/Panda3D/.