That one were Mario and his green brother jump on stuff. /s
Seriously I've never been able to narrow it down to a single game. SMB was my first, but SMB3 is my fav NES game. I also very much like SMW. SM64 changed my view on what a video game could be. SMRPG was good, but 1000 years door really impressed me for some reason. Sunshine was the reason I bought a GCN and probably the game I posted about the most. Of course Galaxy is awesome. In the handheld environment I think SMB deluxe is the best version of the game and SMA4:SMB3's eReader levels were an awesome addition. M&L:SS is on of my all time favorites. So, inclusion, I can't decide.