I've been in the same boat! I played video games unceasingly and did all nighters regularly. It was all a waste. I totally quit them now and am literally on these forums to spend my time instead. I have no idea what else to do.
But these forums are very active and there are lots of questions that people ask. I like sharing the things God has given me. This has been rewarding.
I'm in school right now for the next year then I'll have to start working again. So for a whole year I've got a lot of free time. One thing I know that is always good to get into is exercise and training. I plan on getting into it again once I can get my health to be stronger.
Other things to do are certainly reading the word both day and night. Surrounding your time with the word keeps things strong and safe and this is what we are told to do in the word of God:
This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success. ~Joshua 1:8
Other than that doing something productive is the key. Playing music, playing a sport for exercise, writing a story or poetry, researching about something to know the truth of it, learning to cook better more surprising dishes. I guess that's what life is all about now without video games: getting into the game of life.