Palma is a lightweight content delivery framework for interactive, multi-language, multi-site, multi-channel and multi-device enabled web sites. It is written in C#, comes with MS Access databases by default and is open for Visual Studio Express Edition.
OmniPortal was built on the idea of having a web-portal-kernel, that could handle security, themeing, and localization. This means that you can create any web based system on top of OmniPortal (i.e. ERP, CMS, CRM) easily. Mono and .Net is supported.
ManagedFusion was built on the idea of having a single Web-Portal Core, that handles modules, security, themeing, and localization. A CMS, ERP, or CRM can be easily created with this powerful framework. Mono and .Net are supported.