Vancouverites love being outside (notably, if hiking is involved), and many love adrenaline rushes. Jumping off of cliffs after a hike is the ideal combination of these ambitions. Although the jumps can be hard to find, they are worth it.
If you've got a bit of time in Vancouver (it will take time to find the jumps, and to get to them - notably, if you don't have a car), this can be a great way to spend a summer afternoon. Locations of the cliffs will be posted in the comments.
Don't forget a towel.