Surely vitess (http://code.google.com/p/vitess/ http://code.google.com/p/vitess/) would be one. Written by and for YouTube. (I haven't looked at that code too c

Surely vitess (http://code.google.com/p/vitess/ http://code.google.com/p/vitess/) would be one. Written by and for YouTube. (I haven't looked at that code too closely though.)