If Clustrix offered cloud-based deployment of their database, they could have a small free tier for people to play around with. Add a console applicaiton for accessing the API. Make it really developer friendly.
Imagine if you could just type:
$ sudo gem install clustrix
$ clustrix create my-test-app
Created cloud.clustrix.com/my-test-app
username: my-test-app
password: xd634shx
If they had that, I'd be trying it out in a flash. Then what if they had a per-usage pricing system like AWS? Something where you pay per gigabyte. Something that allows you to test stuff out for a few dollars a mount, and then when you're ready, scale it right up to a few thousand or more.