Riding at high speed, turning 360º, feeling the strength of the wind and discovering the excitement by skimming on churning white waters of the Papagayo River.
A tip for people looking for a decent coffee shop.. if you don't already know about it, you will because most Contiki travellers find out about it - its The Grasshopper. Ask a local and they should be able to tell you where to find it.
If you have a high-def video camera, be sure to take it on a hike with you to the bottom of the canyon. HD is the only way to bring out the gorgeous contrast of blue sky and red rock that you'll want to show everyone at home.