Slightly OT: How addictive is minecraft? It sounds great. But I quit video games a few years back, and don't have good willpower with them. I work from home as well, so there's no natural limits on my time. But I'd love to try the game in a limited way.
Minecraft can be extremely addictive. I know from personal experience. To give you an idea, I'm a freelancer and for a large percentage of last year I was playing more hours of MC a week than I was billing clients. You sound like you may be similar to me with games so let me lay it out for you. When you first start playing you know nothing. There's so much to do and learn. You'll be scared of nighttime and dark caves…
This makes the pocket and xbox edition experience quite a bit different from the PC/servers version.
My experience was I made a lair basically tunneling out an entire 100x50 ish island, built a tower going up until I was bored and a spiral staircase from top down to bedrock, then dug what amounts to a giant multi-lobed endless loop subway just above sea level around the map (probably about 4 minutes, yes that is indeed a lot of mined/smelted iron, and gold/redstone to boost my cart up to speed) diverted into optimized partially-automated chicken production, then got kinda bored. I think I got about a hundred hours of fun out of it, which, for what it costs, is an excellent rate of return.
It reminds me of an old saying about "second life" from about a decade ago, where if you can't be entranced by it for at least a dozen hours, there's probably something wrong with you, but much after a hundred hours or so, its kind of boring.
A third comparison of about equal depth and entertainment was playing Eve:Online also about a decade or so ago without joining any social groups (which was impossible because I was scavenging random hours here and there, and clans wanted dedicated scheduled mining/raiding nights and such)
All three share the characteristic that its hard to go beyond a hundred or so hours without the community, although if the community drags you in, then you're stuck in there forever.
There's probably a startup lesson in here that if you want more than 100 hours of engagement, its going to come from the community, not the programmers / artists / suits.