I'm pretty sure this guy goes on this website, not sure what his username is though. And being the Railgun mega fan I am, I ran into this Only my Railgun cover yesterday, and it was just released, albeit its been almost 2 years since Railgun came out, but still REALLY good imo. Perhaps one of the best?
EDIT : Can anyone see this? It doesn't show up for me and idk if I embedded it correctly >< // If not, here's a link
http://www.youtube.com/watch?v=jBl-RgTat5I