Elastra - On Demand Applications in the cloud
One of my VC friends pointed me to Elastra. I think the idea of creating scripts to provision entire servers built up to the application tier in the cloud is v cool.
6 years ago, I used bladelogic (recently acquired by BMC) to manage server configurations. Elastra offers similar features in cloud computing. It makes cloud computing more accessible.
Here is review of Elastra on GigiOM.
UPDATE: I also like Rightscale - they compete with Elastra. Rightscale on GigaOM.