When you jump from object to object without touching the ground, and/or "Lava". Kinda like what you played as a kid...but cooler. It can be spelled Parqour or Parkour. This is not reccomended for the uncoordinated.
"Dude, lets parqour to the truck."-Jon
"Oh yea, i'll jump from the ledge to the stool to the truck."-Tom