I love vim-adventures. It was the only way I was able to stay motivated to learn vim well enough for it to "stick". I just hate that you can only buy 6 month access to it. I'd happily pay 2-3x the price for lifetime access, but the fact that I can only buy 6 more months makes me pretty sure that they won't be getting any more money from me. I think I would still hop on for a few minutes every few months to practice up on some stuff that I forgot.