Parkour Fortress: approaching open beta
Shameless plug time: the sub-community we gave Parkour Fortress development to (parkour.tf) is holding open betas - you can find more info on their group here: https://steamcommunity.com/groups/parkourtf/
For those who don't know what Parkour Fortress is - it's an old, abandoned mod, which can aptly be described as Mirror's Edge in Team Fortress 2. featured on the now dead Slag Gaming, created by Mecha the Slag aka MekuCube aka Jonas Kærlev, the same developer who went on to create one of the most loved 3D collect-a-thon platformers in recent years.
Sadly, the original mod was not open source, and has since been left to slowly fade from memory until parkour.tf picked up development of a modified recreation, being tuned for surf-esque competitive running.
It's far from finished, but give it a whirl. It's still in beta, so a lot of bugs are to be expected.