The Internet Archive aka "The Wayback Machine".
The Wayback Machine stores a backup copy of the internet. Very useful for when you get that ol' "404" error. But the other use for it is that people legally upload documents, video and audio for archival purposes. It's a kind of digital preservation society. And there is a good selection of Beethoven saved there. Clicking the links below will get you started:
CHARM: The AHRC Research Centre for the History and Analysis of Recorded Music.
CHARM has a massive archive of recordings from 1915 to 1952. It can be organized easily by Composer, Conductor, Artist Title or Year of Recording.
For Composer select B, then pull down the slider and click on Beethoven (224 tracks). In the Artist column you will see all the performers. You can choose a Year as well.
Once you click on Beethoven you will see all the music below. You can instantly play the piece by clicking on the "play" button (sometimes twice is necessary). Or you can download it to your computer.
I wish I could provide direct links to some interesting finds but unfortunately I can't figure out how, so just play around, you never know what you may find...
Here I found Ravel conducting Bolero himself...