Beartooth Basin yo! It's in between Red Lodge MT and Cooke City WY along the Beartooth scenic highway, a little ways northeast of Yellowstone.
The lifts are (were, I guess, since they just sold it) run with a 1975 Detroit Diesel generator. The first time I went I remember someone saying something along the lines of "don't ski over the electrical cable dickwad, or we're all fucked," hahaha. The generator powers two oldschool poma lifts up the steepest, gnarliest cornice you can imagine. The lift towers were installed way back in the 60's when it used to be a private race camp and people weren't such pussies about liability lawsuits, no way anyone would have the balls to build it now. The ticket office is a trailer in the dirt lot at the top of the resort. Tickets used to be just a piece of paper duct-taped to your pants (they got legit stickers now!), and they do $20 power-hour specials because the owners are generally rad dudes who are all about getting people exposed to their gem of an area. The park is set up mostly by local volunteers, and they do an awesome job keeping it safe, fun, and well-groomed with the few tools they have... could really use someone like yourself to help out sometime actually ;) Typically a 6-8 week summer season from late May to early July, sometimes longer if the snowpack is particularly good. The highway is pretty much buried in snow for the rest of the year and is basically impassable unless you're on a snowmobile.
ON3P does the annual Beartooth Summer Session there and the area/event is starting to gain some traction with the NS-crowd. I can't fucking wait to go back.