Three quick points.
1. By-election is a much, much, better name than special election. We Americans need to get to work and invent a better name for these things.
2. I love election day. I won't repeat my riff on it (see here), except to say that for my money if you don't enjoy this great democratic ritual, you're not as patriotic as you might think you are. Also, I wish CNN would bring back the holograms.
3. As far as what it all means, I'd like to say something smart, but I couldn't top John Sides. Go read what he has to say, and then sit back and enjoy yet another extra bonus patriotic treat.