For those who wanted to try OpenStack, you might want to consider testing it in TryStack, a free service backed by Cisco, HP, Dell, Equinix, NTT, and Rackspace. They provide 156 cores, 1040GB memory and 59.1 TB of disk storage running OpenStack cloud software. What's best is that this service is free of charge.
All you need to do to create an account is to join their Facebook Group and receive a message from the admin containing the username and password that you can use to login into your system. Once you get the username and password, you can login to the Dashboard or start learning the API.
What are you waiting for? Go join the group!!