I recently did a quad biking tour with Medellin Adventure Trails. It was pretty awesome, covering some technical and demanding trails. The quad bikes saw mud, sand, clay, and we even drove down a river for about 1 kilometre! good times. I can highly recommend Medellin Adventure Trails for an extreme off-road quad bike trip if you're ever in the area. They cater for less experienced riders too.
The tour is actually located in Guarne, about 40 minutes from Medellin.
medellinadventuretrails.com
MUSIC: "Engine Fire" from the YouTube Audio Library