So, though I've just landed into two new campaigns and have a third running, I'm a fairly solitary guy. Thus, I was looking into solitare games. I'm talking RPGs, skirmish games, things like that where I can jump in, do a scenario, then get on with work.

I'm looking at Castle Ravenloft but holy geez it is expensive for me right now. I like how the monsters have built in AI, though. Anything like this that's cheap or free?