Also there was http://realtimerelativity.org/ http://realtimerelativity.org/ a while ago, which simulates motion pretty close to C. Don't know which one is more

Also there was http://realtimerelativity.org/ http://realtimerelativity.org/ a while ago, which simulates motion pretty close to C. Don't know which one is more "realistic", but it shows much more pronounced effects