If you prefer to keep your feet firmly on the ground check out the Rio Celeste Volcano Hike - or go Four-Wheeling with the Arenal ATV Tour. Motorcycles and scooters are also available for rental. Or If you prefer 2 wheels to 4, hit the trails here - with a number of bike rental companies.
If you really dig the Earth, go underground at the Venado Cave tours. Flashlights, helmets, and snacks are provided.
View the local wildlife from the back of a horse on the trail to La Fortuna Waterfall.