As a victim of way too many Facebook games, I'm happy to point to these two amusing - and productive - web games that are my new addictions.
The first sounds like a Joss Whedon creation: Dr. Wicked's Writing Lab. My friend Ralph turned me on to this. It's less a game than a funny challenge, but it works - as long as you don't just do it to hear all the gripes and buzzes. But then, I knew a guy who used to play Tomb Raider in order to see all the ways Lara Croft could die. Laughed himself silly. It takes all kinds.
The second of my current addictions is definitely a game, despite my referencing it as "research." Gladiatusis a free web-based gladiator game that forces you to walk away. Fights happen in five to thirty minute chunks, during wgich time you can't do anything else. Fantastic. I get up and do dishes, or do some actual research, or edit. Next time I'm online, I notice the minimized box and say, "Oh look! It's done. Did I win?" Hardly time-consuming at all.
So, for the New Year, test yourself by writing against the clock, then play the game that gives the best gift ever - the time to do other things.