Since you mentioned the problem seems to have started due to issues arisen from dealing with people in online games, it seems likely that these people are attacking you after they see you log into those games. Even if the game is client/server based, there may be some mechanism for them to obtain your IP address (direct messaging requests, lookups to see if you are online, etc.).
So, my suggestion would be to stop playing the games (or even joining the networks hosting them, if possible) for a while and let the unsavory characters find under people to harass. You can then go play some different games on some different gaming networks. Eventually, they'll probably think they've scared you off permanently and drop you from their DDoS list, and you can go back to gaming on that network.
Alternatively, you could look into using a VPN to tunnel your game traffic to a box outside your network, but you run the risk of annoying the VPN provider if their network gets DDoSed. Still, that at least transfers the problem off your home network, and it could be the VPN provider is in a better position to mitigate the DDoS than your home ISP.