Another package manager that is mostly dead nowadays is Horn. Even though development has mostly stopped now, I think it is/was an interesting project.
It took an interesting approach to package management, based on compiling from source code first instead of relying purely on binary packages, in a similar way to gentoo portage's ebuild. This gives the developer ultimate freedom to mix and match library versions (as opposed to waiting for project mantainers to officially update their dependencies), but as they say "with great power comes great responsibility", it is also up to the developer to make sure that the stack he compiles does work.
Of course you could play it safe and instead of building everything from trunk you could fix dependencies versions in your descriptors (for example, there is one descriptor for Castle Windsor trunk and another for Windsor 2.1).
For those that didn't want to build everything from source (which is naturally a very slow process), there was a server at hornget.net that acted as a continuous integration server and provided binary packages.
NuGet (formerly NuPack) is a free, open source developer focused package management system for the .NET
Openwrap is what I choose to use. This was developed by the community for the community. If you support MS spoon-feeding "OSS" tooling, then you don't have the right idea about OSS.