I picked up a fat bike (Kona Wo) a couple of years ago, mostly for winter riding, but I've been checking out some of the trails in the Twin Cities over the last year or so. I'd call what I'm doing more off-road exploring rather than mountain biking. There are a lot of trails around here and I can go somewhere new every weekend. Since I'm not familiar with the trails I'm not comfortable going too hard -- I do enough of that on the road.