Advice needed on Internet content filtering

[Dog80]

I have a problem at work. We absolutely need an internet connection for placing orders, checking availability of products etc., but some people spend a lot of time on YouTube and stuff like that. So tomorrow I am getting a new Zyxel router that has content filtering capabilities.

What I need is a list of websites that are 100% work unrelated, like youtube, metacafe, Fark so I can block them. Are there any available for free or do I have to make one of my own?