Vagrant is an open source tool that allows you to programatically create and manage virtual environments. Vagrant's main focus is on creating development environments that can be shared between teams all over the world. It removes the "works fine on my machine" problem and allows anyone with the Vagrantfile configuration to create an exact copy of the original machine.
Vagrant was created and is maintained by Mitchell Hashimoto and HashiCorp with a continuous stream of support and updates. It's a piece of software that has been going from strength to strength since its creation in 2010.