Blink SWEP
What is it?
The blink ability from "Dishonored", in SWEP form. Also features double jump.
Why do I care?
Because you can woosh around from rooftop to rooftop with it.
How do I use it?
Give yourself the weapon, hold left click to charge, release to teleport.
You can aim at a ledge and it will snap to the top of the ledge for climbing.
If you have the SWEP, you can also hold your jump key to double jump.
Caveats
Aiming around corners and at ledges can be problematic. This is just how it works, and is to prevent players from getting stuck in walls. Sorry.