LEGO Bulldozer 60074

Well, I loved building this for my 4-year-old son, who is not quite old enough to do it himself, and he loves playing with it, so it's a win-win. It's actually a slightly more complicated build than expected, although those aged 6 and above shouldn't have too many problems with it. When built, it's a decent size and I like the fact that the front lifts up and down and the tracks work properly (although they were relatively fiddly to build).