Giving up video games in my 20s. If I hadn't done that, I'd still be stuck in front of a game somewhere. Those things will eat your life.
However, there are several ways to enjoy video games these days that involve a community and are much healthier. And I am not talking about a massively multiplayer game where the "community" is really just another gameplay element pulling you in. I'm talking about an external community that draws you to actively participate, to enjoy the game for something more than what it is at face value. This comes in many different forms, and I think most people would be hard pressed to say that they are "eating the life" of anyone. Maybe I can just list a few of them and let you decide:
1. Speedrunning community. I list this first because it's my favorite. Speedrunners revitalize games old and new by practicing and playing them to almost complete technical perfection. The communities are large, positive, supportive, and full of energy. Both speedrunners and viewers get to enjoy games they already loved in a completely new way, and engage in a meta-competition that is much more tangible and community-oriented than numbers on a screen beside user IDs. There are large communities in both Japan and the US/Europe (though the two don't interact much). The Japanese community generally interacts in the form of videos posted on Nico Nico [1]. The Western community has a forum and video site at Speed Demos Archive [2]. To give an example of the size and positivity of SDA, in particular, they run several marathons a year like this one [3] that draw thousands of viewers and raise tens of thousands of dollars for charity.
2. Indie game development. I don't think I need to say a lot about this; this community interacts enough with HN for its vitality to be clear enough. Even for lone developers, the creative aspect makes this a healthy pursuit.
3. Romhacking community. This is related to the indie game development community in spirit, but on a much more casual level. Using tools built to quickly make levels for games like Sonic and Super Mario World, members of these communities make completely new games out of old engines and assets. These new games - called "romhacks" because of the way they are made - are often posted on forums or at sites like SMW Central [4] or Sonic Retro [5]. It's a very unique kind of community that draws together creativity and games. This one is also related to #4:
4. "Let's Play" community, probably the youngest of these. Much like speedrunning, this community aims to revitalize games by playing them in an entertaining way and publishing the videos (which are then called "Let's Play"s or LPs). These videos were usually posted on forums like Something Awful, but increasingly these communities are centered on Youtube. Very often the games played are indie games or even romhacks.
Edit: There is also a community related to #1, the Tool-Assisted Speedrun community [6] that aims to play games to literal technical perfection with the benefit of tools like savestates, frame-advance, and recording provided by emulators like zsnes. Such tools are obviously frowned upon in the normal speedrunning community.
[2]: http://speeddemosarchive.com/
[3]: http://marathon.speeddemosarchive.com/
[4]: http://www.smwcentral.net/