There's http://ckan.org http://ckan.org (disclaimer, I work with this) and http://dataverse.org http://dataverse.org if you're more academically minded. There

There's http://ckan.org http://ckan.org (disclaimer, I work with this) and http://dataverse.org http://dataverse.org if you're more academically minded. There are others, but hard to judge any claims of open-sourceness without access to source code.