Thanks to the Keanu Vision archives! A post on November 24, 2004 mentioned that Richard Gere and Keanu Reeves narrated a series called Discovering Buddhism.
Discovering Buddhism is listed as a documentary on IMDb. It was designed as a 13 part series that was co-hosted by Keanu Reeves and Richard Gere and was released on January 1, 2004 which would indicate that it was filmed in 2003 sometime (if not earlier). Google blurps indicate that the series aired on PBS.
At the very least, Keanu appears in an Intro clip (starts at 1:56 min mark) and he hosts module 4 (1:30 min mark), 6 (1:30 min mark), and 7 (1:30 min mark). The clips are on youtube and are here, here, here and here. The very first one is below.
Note: I plan to get them all downloaded and pull out Keanu’s parts for the media room. That will take me some time so you can go to youtube in the meantime and go to the given mark if you aren’t interested in watching the whole clip.