The “Runkfunkbeitrag” is a mandatory bill paid by every household in Germany. “Rundfunk” can be translated as radio or broadcasting, and “Beitrag” means fee. For a while, this was not a mandatory payment as long as you could prove that you didn't watch public broadcasters like ARD and ZDF or listen to the radio. However, since January 1, 2013, the payment has been mandatory, regardless of whether you can prove you don't have a TV in your house or not.
The fee is not hefty, however. It is taken out in 3 month increments, with a monthly cost of 17.50 euros. Thus, in total, you'll receive a quarterly charge for the GEZ (Gebühreneinzugszentrale) of 52.50 euros. This is, however, a per-household total. Thus, if you live with two other people, you only have to pay less than 6 euros a month.
One of the only ways to avoid this fee is if you are a university student who receives German financial aid. Thus, when you are selecting a dorm to live in and choosing your group of roommates, it makes sense to ask who is receiving “BAFöG” (financial aid) for the purposes of the broadcasting fee. This is important information to have, because if you live by yourself and allow these bills to add up, you could potentially be sued by the GEZ. Some believe it is worth the risk, but better safe than sorry!
The great benefit of paying this is that you will be able to hook up any TV and automatically receive hundreds of channels, including many from abroad. For example, two of the English-language channels available are BBC and CNN. You also have full access to many German TV stations online. So play it smart - pay the GEZ!