Chris, I have a 4.5 year old boy. We have PS2. My son is an addict. We have several PS2 games (I have a 7 year-old too) but the ones my 4.5 year old loves are Lego Star Wars, and Lego Star Wars 2. There is a lot of fighting with light sabres and laser guns but it's pretty benign. And when I play with him, I get hooked and suddenly a half-hour is gone....
The advice about making processing time enjoyable is right on. This is one of my techniques for completing ANY tedious process. For example, I have speakers over my sink and I plug in my iPod when doing the dishes or emptying the dishwasher. I think I learned this technique about 15 years ago, from Anthony Robbins. He wrote something like, "Ask yourself, how can I do what I have to do and enjoy the process?" This has always stayed with me. When I give this advice to others who I observe doing boring work - or procrastinating boring work - they always react as though it never occurred to them. It's a master key to getting things done!