Maybe it's the company I keep (on Twitter and the Fedora Planet anyway), but I keep hearing about Docker and its use of Linux Containers to deliver stand-alone applications:
Docker is an open-source engine that automates the deployment of any application as a lightweight, portable, self-sufficient container that will run virtually anywhere. Docker containers can encapsulate any payload, and will run consistently on and between virtually any server. The same container that a developer builds and tests on a laptop will run at scale, in production*, on VMs, bare-metal servers, OpenStack clusters, public instances, or combinations of the above. ... * Please note Docker is currently under heavy developement. It should not be used production (yet).