The good folks at Carnegie Hall have published a fascinating video (mostly) guide to the string quartets of Bela Bartók. The guide is hosted by members of the Emerson String Quartet and is called, fittingly, The Emerson String Quartet: The Bartók Quartets, A Guide for Performers & Music Lovers.
It's a little like watching a well-produced bit of television on the subject. The Quartet's members are talking heads throughout and, when examples are played, the appropriate section of the score pops up for your viewing pleasure.
All six Bartók quartets get a going over, including No. 3, which the Emerson will play on their Celebrity Series program at Jordan Hall on May 12 with pianist Leon Fleisher (No, Mr. Fleisher hasn't taken up the violin, he'll play Brahms' Piano Quintet in F minor, Opus 34 with the Quartet). The May 12 concert date should give you plenty of lead time to get up to speed on Quartet No. 3...
A mild note of warning: in my experience, the Performance Guide requires a very speedy connection to be viewed adequately. This isn't really Carnegie Hall's fault, of course; but though the developers have included some controls to let you goose the quality/speed ratio a bit, the video and audio were still choppy for this user. I'm sure others will have a better experience.