Help me block proxiers please.

I need a script that blocks all proxies that come into the site meaning if someone uses a proxy they can't get into the site. Does anyone know how to make this? I own a game and people get clicks by getting people to click their secret link. Well they are using proxies and making the proxies seem as if they are clicking the link over and over so they get clicks fast and easy. Well is their a script out there that blocks proxies...please reply soon