Hang gliding, parachuting, kayaking, rafting and water skiing.
For a first visit to Medellin, the site described here is relatively easy and accessible.
Thermal flights, ridge soaring, and long XC flights are all possible from this site.
As it is adjacent to a large metropolis it is also rife with hazards (power lines, restricted air zones, antennae), so be sure to receive a thorough briefing from local pilots, many of whom speak English quite well. This is a popular site so you can count on someone who can help you.