Recently I've noticed that Comcast users (including myself) have been having issues losing connection during games. Frequently, up to 3 or 4 people will lag out and disconnect at the same time, and when I ask, everyone who has the issue gets their internet through Comcast. It also happens with lag spikes without disconnect. I will get a lag spike, ask other people, and discover that 2 or 3 others are getting the same lag spike. Usually, however, it doesn't affect my connection to Teamspeak, which makes me think that it is a problem between League and Teamspeak.
Please upvote this to get attention. I'm also posting it in GD.

This just happened to me today. My internet went out for about 2 hours during a game and I ended up getting my first leave. A bunch of my friends who use Comcast also got disconnected.