Despite being somewhere that you sleep, ION's labeled itself as "Iceland's first adventure hotel", a claim it backs up by being located on the edge of Thingvellir National Park (literally: "Thing Fields" -- way to go, Iceland's park-naming team!), which packs a pretty hefty dose of non-slumbering activities
The hotel itself is actually perched up on stilts, slapped next to a geothermal power station, and stuffed with 46 rooms, and bar & a resto.
The adventure portion they're boasting about? Well, for one, you can go snorkeling between two tectonic plates, specifically the ones separating America from Eurasia, and which, if you're not careful, will veeeeery slowly crush you to death.
On top of that, they have "superjeep" trips through the snow to see the midnight sun during the Summer, when there's 24hrs of daylight and zero vampires.
Also, white water rafting
For water moving at a slightly more amenable pace, you can hike up the local glacier Solheimajokull, and stumble over its icy surface/insane pronunciation
You can also descend into a literal 2000yr-old lava tunnel known as the End of the Journey Cave (though that's really only if you stop believin').
The lava tunnel, by the way, is there because you're right on top of an active volcano -- the nearby geysers will also attest to that fact, with remarkable regularity.
The lava will also heat this natural spa/pickle party..
... as well as this slightly roomier number in the hotel itself
The spot is famed for the regular appearance of the Northern lights, which they get prediction info on from NASA -- the locals will even turn off the streetlights for the event so you can see them better (or maybe because they have the same budget problems as NASA).
The space even has this Northern Lights Bar, w/ double-high windows for you to booze under & admire
They also have a resto, which serves mostly local lobsters that get wrapped in slow-cooked salmon, parsley root, herb salad & lobster frothing -- and won't be the only thing frothing when you read the rest of the menu
Oh, and the rooms themselves -- they all have floor-to-ceiling windows, underfloor heating, soundproofing (natch!), espresso machines, and a "wake-up service", though surely that's what the espresso machine is there for?