Garbage Collection, ever wanted to learn more? Well here is a chance; Maoni Stephens is one of the core engineers whom you usually wouldn't get access to. She is responsible for the implementation and performance of .NET's garbage collector.
An insightful, must read authored by Kent Boogart where he shares his abstraction that allows you to swap out your application's service layer quickly. By flicking a switch, you can run your application against a simulated back-end.
Another insightful read that explores under the hood of how the CLR allocates strings by Matt Warren whom you may know as one of the geniuses that created this fantastic .NET performance testing library. Miguel de Icaza commented on Twitter that Mono/Xamarin uses the same tricks under the hood.