Post a game that you won't get tired of and will never stop playing as well as keep on playing

There are a number of games that come to my mind but if I had to name one it would be Mario Kart Wii,playing it just never gets old,it's always so fun!

All the old school resident evil games ^.^

Terraria

I can always find something to do on it. I've already got a few characters through all the bosses and got endgame armour and weapons for them, and I've already got every single achievement, but I'm still not bored with it.