Originally posted by: Zenoth
I would say finish all the Super Mario Brothers games there is. I finished SMB, SMB3, SMWorld, and that's it. I never got to actually complete SMB2, SM64, SMSunshine, SMGalaxy and so many others, including those on the Nintendo portable systems that were released over the years. I did play most of them however, I just completed a very small number, and there's some I never played at all, mostly on portables (or some not on portables too, like Luigi's Mansion on the GameCube and others in the same vein).