The centerpiece of the group show Fun House is unavoidably the big box in the center of the main gallery. Smelling of fresh-cut plywood, Julian Hoeber's installation Demon Hill invites you to climb inside, like some carnival attraction. It's participatory, playground art that you experience as much with your inner ear as with your eye. The trapezoidal, open-topped structure is all akimbo—Dutch angles and Caligari floors. Enter through the doorway, ascending a ramping floor, and you're immediately off balance. Reach out to the walls, and you'll find they aren't plumb (though a plumb line hangs from an overhead rafter, as if to mock you). Stand inside long enough, and you'll get a certain woozy, listing-ship sensation. Though wooden half-round strips have been nailed into the floor for traction, women in heels had best leave them outside. It requires concentration to remain upright, effort, a reminder of how we navigate the rest of the city so easily, so lazily, on the horizontal. We take flat surfaces for granted, but the L.A.-based Hoeber won't allow visitors any equilibrium underfoot. (For a more playful variation on the same theme, please remove your shoes before romping inside Mungo Thompson's Skyspace Bouncehouse in the back gallery.) Demon Hill resists the grid, fights linear perspective. Nothing about it is on the level.