Well, my primary experience is in JavaScript, which is all the rage these days. It's pretty much your only option if you want client-side scripting, though there are plenty of languages that compile down to JavaScript in one way or another.
I suppose Arc would also be a decent starting point, given how Arc was built around its webserver. Unfortunately, I don't use Arc for its webserver, so I can't really help you with that. There are a few other people floating around on this forum who have more experience with that sort of thing.
Like akkartik said, feel free to ask any questions you have, whether related to Arc or not. We'll do our best to answer them.
