Central America - Advice on excursions / activities in Guanacaste, Costa Rica?

I will be in Costa Rica from July 7th - 14th, staying at the Four Seasons in Guanacaste. Rather than book excursions through the Four Seasons, I am wanting to find out what is a better alternative for affordable and fun activities. Things like horseback riding, slides, zip lines, hiking, etc. Perhaps there is a tour company or places I can get in touch with directly to try to cut out the middle man?

Contact
Josta Loppé
Papagayo Vargas Tours
www.papagayo-vargas-tours.com/
They do a great job and have a variety of tours. Their river tour may not sound too interesting but we really enjoyed it and have heard rave reviews from all of our friends who have taken it. We went horseback riding and have done canopy tours, sunset sails, and more. Josta is great to work with.
Also - have dinner at Citron in Playas del Coco and at Ginger in Playa Hermosa.
Then, if you want to buy real estate in Costa Rica, talk to Mike Simons at RE/MAX Tres Amigos.
Enjoy!

In other parts of Costa Rica I've picked up a local paper when I got there and went through the ads. I ended up getting some good deals on surfing, rafting, canopy/zipline tours and massages that way as the ads led me straight to the operators so I avoided paying a middle man to do the bookings.