Note 12/02/96: Laurens Lapre has done a lot of nice work with lsystem generated objects. He has a VRML scene of a 3d Hilbert curve that you can fly through in your favourite VRML viewer.
The frames were generated with Persistence of Vision, a great freely available ray tracer that runs on most platforms - UNIX, Mac, DOS. The distribution is available via ftp.
The object itself was generated with Jon Leech <leech@cs.unc.edu>'s excellent L-system software (available by ftp), modified by me to output POV data. I then took the object and put it into a simple scene, rendering it with plain white cylinders and some naive lighting. This is the part that indicates I'm not a raytrace artist.
For each movie I generated lots of different frames using POV-Ray and then pushed them through the pbmplus package to generate GIF files. Then I displayed the GIFs as a movie using Mark Podlipec's xanim software, a nice quick tool for showing movies (available via ftp, as well as a WWW document). For export I've converted them to MPEGs using mpeg_encode (once again, for ftp).
I'm not happy about the MPEG quality, but they're relatively small and more convenient than a big list of GIFs.