I don't know the game "Food Fight", but whether that project is feasible doesn't depend on which language you implement it (assuming sane languages like Perl, PHP, C++, Java, and not INTERCAL or sendmail.cf).

I'd first decide whether I'd do it as an applet (which would limit the number of languages you can use), or as a pure browser game. The latter brings some restrictions. Or rather, one restriction with consequences. The restriction is that all communications goes over HTTP, which is essentially a state-less, connection-less protocol. Cookies have been bolted on top of HTTP to get some form of states, and there's keep-alive and HTTP push to get partially around the connectionlessness as well, but it's awkward.

I'd first design how to do the communication between the clients (players) and the server. What state do you need to keep? How does a client register? What do you do with unresponsive clients? And I'd write it in a language I feel comfortable with.