Pretty often, actually. Comes with having a decent backlog. That said, I make an annual point of playing Paper Mario and one of the Zelda games, and that occasionally devolves into playing three or four of them. I have constant restarting and replaying of Earthbound, Mother 3, Chrono Trigger, and Super Mario RPG on my phone. I just finished a Pokemon binge up to gen 3, collecting each 'mon (and caught my first shiny!).
I'm currently playing FFX and Secret of Mana for the first times, being in need of a really good RPG with a bit of grind to it that I could just sink into without having to spend twenty hours in a tutorial before spending five hours and finishing the game.
The last recent title I played was South Park: Stick of Truth, and that was over in such a short time I barely had enough time to say I was enjoying it before I'd consumed it, like a small cup of ice cream. Short of Dark Souls, I haven't found a game where I could spend sixty hours in recently, and I've been craving for that. And old games offer that in abundance.
I call my hydroelectric-plants-on-a-mound "anthills", but that takes up too much room.
