Is it ALT.NET or Progressive.NET and who uses it?

I'm interested to find out the correct term for the stack based on open source tech such as nHibernate, Ravendb, Service Stack, Booksleeve, nUnit as opposed to Microsoft tech such as WCF, TFS, MSMQ

I really like C# as a language and .NET as a runtime but no-one wants to talk about using it unless they are a large corporate using Microsoft's products.

I want to belong to a community but I don't know its name or location!

What companies/startups (aside from Stack Overflow) are built on this tech and are willing to admit it?