You can deploy openstack environment on various host OS, for me the easiest is using ubuntu trusty server image.
If okay with you, go ahead download ubuntu server ISO from http://www.ubuntu.com/download/server and create a Virtualbox VM with 4KRAM and 20GB storage.
Then, if you want to get a first-look on openstack, you can deploy openstack on the ubuntu VM you created. Read and follow steps on http://docs.openstack.org/mitaka/install-guide-ubuntu/ (http://docs.openstack.org/mitaka/inst...)
If you want to try some code change, you can deploy openstack development environment on the ubuntu VM you created. Read and follow steps on http://docs.openstack.org/developer/devstack/ (http://docs.openstack.org/developer/d...)
Good luck
Perhaps consider http://www.mirantis.com
It's very easy to get Openstack running using their virtualbox/fuel solution