Many people I run into are looking to learn about OpenStack, and in particular, how it works with VMware products like vSphere.
While there are documents, presentations, and video demos available online, nothing quite beats trying out the real thing.
VOVA is an OVF virtual appliance that you can download, provide some info about your vCenter environment, and be off to the races.
This should not be used for or along with any production workloads, it is just a learning tool, and is brand new, so there are bound to be glitches.
Check out the VOVA Manual for details and the link to the OVF, and feel free to ask questions in the discussion forum in this VMware communities page.