Soon there are European elections. Voting for the Pirate parties and getting other people to vote for them is a good way to stop this. They are fighting hard against this law. Especially Patrick Patrick Breyer of the German one. Anja Hirschel, who will follow him, will likely continue with the same vigor.
Donations are also a great way to support. Donate to the Pirates, EDRI, or local groups opposing this.
Well there is the Stop Killing Games initiative started by Ross Scott and supported by the Pirate Parties. If they succeed, companies selling games in recent years will be required to either keep supporting their game or to make it available in a way so that others can ensure its continued support.
When this is achieved the step to free older games is small.
If you live in Europe you have the chance to support the movement by vote in the upcoming elections.