My partner and I had had a poor experience at one of the organised cloud forest sites, so we needed an interesting activity for the afternoon. We saw it on the map and set off on a 2+ hour walk down hill. Had no idea what to expect. It was down a long long road with amazing views of the coast. We got there and was welcomed by a lovely family. Paid them $8 (if think) and walked through their garden for another 20mins. We were the only people there and it was fan-blooming-tastic. It change my view of Monteverde 100%.
We sat in their cafe eating homemade cake and watching the local wildlife for over an hour and then got a taxi back for $20.

A grueling drive, but once you're there, it's a 30-minute hike to one of the most spectacular sights in this section of Costa Rica. Go early (arrive by 9 or 9:30) and you'll most likely have the waterfall to yourself until 11 or 11:30.

This is a must see if you are in the area. Make sure to walk all the way to the really big falls. We took a cab from our hotel (Hotel Belmar), and the cab waited for us while we hiked it (maybe 45 minutes one way, 15 minutes swimming) - $40. Also there was a $10 per person fee to the trail. The hike was not very strenuous, but was scenic.

A must see in while in MV!
I took the public bus from the Municipalidad de Santa Elena all the way to the entrance of the San Luis waterfall for a quarter.
From here, the walk is about an hour and a half from drop off to waterfall. The views along the way are absolutely magnificent, so be sure to bring your camera. There is also one convenience store about halfway there should you need more water or a snack.
Once to the beginning of the trail to San Luis waterfall (which is the home of the owner of the land), the cost is about seven dollars (I think?) to hike to the waterfall and stay as long as you'd like. The hike is awesome, and although not really strenuous, there are some mini bridges to watch your step on.
Once at the waterfall, JUMP IN! The water is really cold but it is so pristine.
When you make the walk back to home of the owner, they are more than happy to call you a ten dollar taxi back to Santa Elena if you want it. If not, just get your walking legs ready for a mostly uphill trek back.
Enjoy!