I think they're lamps made out of beer bottles (just with no lightbulbs installed yet, they'd sit in the top).

Light beer lights.

Further context for those outside US:

The bottles are from two of the most common, cheap domestic beers, which can be found everywhere but are strongly associated with low-brow party culture of the suburbs and the holler (tailgating, barbecues, etc). Like, if you order one of these at an upscale place, it’s probably either to signal approachability / lack of pretension or because it’s the cheapest thing on the menu.

Also making do with what’s at hand, aka “redneck engineering,” is a meme in its own right.

Edit: not turning my nose up, to be clear. (Though if I’m picking up a case of cheap beer, it’ll be PBR or Schlitz if that’s still around. Maybe non-light Coors.)