Internet and social addictions are real. There are many IRC chatrooms that are filled with people who haven't done anything, not a single finished project or any sort of plan with their lives, because they are too busy filling the craving of talking about whatever, or "planning" to do something/"hoping" to finish a project, and so on.
I'm also someone who has recently shook off gaming. A friend of mine tells me I am doing it wrong because I should be enjoying life, however looking back I sank way too much into SC1, Day of Defeat, Counterstrike, and was almost baited by SC2--the same games that Matt Rix mentions.
I prefer to play Single Player nowadays because there is a definitive start and finish. This acts as a cue for me to get back to work if I have been slacking off too much.
For me, once I get over the initial plateau of starting up again from where I last left off on a project, the feeling of laziness and procrastination goes away. Again, Matt mentions knowing the concrete things you wish to do and then executing them. It works for me(tm).