I love movies and I especially love commentaries. So I got myself a microphone and produced some of my own. I do commentaries alone (and occasionally in collaboration with the Doctor of Speakeasy, my little niece, or my dog Jet Jackson, Space Dog) and post the results in MP3 format with a bit rate of 64 (higher, for collaborations with the Doctor).
UPDATE 2014: I now do commentaries with several collaborators, including John Pavlich of Sofa Dogs, Drew from Trek.fm, Soulless Minions, the Film Bin crew, and guys from the Friends in Your Head forum, as well as the Dr. and Lynch from Speakeasy. My niece (and nephew, who helped on Star Wars) are 11 now, and we still watch movies together every few weeks. Sadly, Jet is gone, and his replacement, Dame Katherine Foxwell (a.k.a. Kit Foxy) doesn’t come down to the theater, but her playful barks can sometimes be heard in the background.
As a movie lover in general, I try to call out the similarities and differences in the film I’m commenting on to other films in the same genre. I try not to spoil those other films, but you never know. I’ll try to warn you first.
For other commentaries, I recommend our sister site: Zarban’s House of Commentaries.
If you wonder about microphones, I used a Logitech USB desk mike for the first bunch of these, but since Vanishing Point (#36) I use a Samson CO3U, which has better bass response and consistently captures cleaner sound.
I’ve used a variety of methods to help you keep in sync. My early commentaries include occasional time codes, which I realized are useless if you watch the movie in a different format from mine. Starting with Frankenstein (#37), I began to use my exclusive “EchoSync” technology, which involves me speaking dialog (with moderate reverb) at the same time as the characters. That turned out to be fun but laborious, so now I often just read subtitles as they are displayed and try to make direct references to what is going on on-screen.