What OS software is missing in the .NET world?

Question

I'm a .NET developer working alongside Java and Eclipse developers. They seem to work with a lot more Open Source than I ever have. Some/Most seem to have made it across to .NET (Hibernate to NHibernate is a great example of this.)

But I am curious as to what OS software out there hasn't made it to the .NET world? What do people feel is missing. I'm interested in both business applications and development tools.

(Background: Asking this question to myself made me think realise that I would like to fill in the holes, if there are any.)

Thanks

Edit: In light of the recent CodePlex foundation creation perhaps the answers here might suggest the kind of projects we'll see coming along.

Edit: Great responses so far, please keep 'em coming.

Answer 1

Well (for example) as hacked up and unsecure as Wordpress is, it's still a lot more full featured than BlogEngine.net. And as much as I thought the learning curve on Drupal was too steep, I found the ASP.NET CMS products dominated the territory that lay between expensive and unusable.

Until recently, Microsoft has fought the open source community instead of courting it, and for their part, many of my fellow users of Microsoft tools share my expectation of being paid for our work.

Answer 2

SharpDevelop still needs a lot of work to be a viable counterpart to Eclipse, so if you're into tools, that'd be a great place to contribute.

Other than the still experimental Machine.Migrations, I don't think there's a good equivalent to Rails-style database migrations.

Answer 3

Hadoop is a good example.

http://hadoop.apache.org/

AFIAK there is no open source .NET equivalent. It's a shame really, it's a really nice framework for clustered software.

Another example is the GNU Scientific Library:

http://www.gnu.org/software/gsl/

I would say that in general math/science routines are very lacking in .NET, IMO .NET is currently heavily biased towards the data driven developer, as apposed to the scientific developer. For reference: System.Data is a massive namespace, System.Math is a single simple class. :)