Argolis is a set libraries built around NancyFx library.
They allow building Hydra APIs with relative ease, where the development is not much different from any standard .NET web application. Instead of forcing RDF model on the developers, standard .NET practices can be used with POCO classes, layered architecture and endpoint-based API definitions.
Argolis then simply integrates with the response/request so that consumers can take advantage of Hydra API descriptions.
When Argolis was starting a few years back, Nancy was probably the best API library
for the .NET Framework. Recently the ecosystem changed a little bit with the refreshed
stack and inspired solutions like Carter.
Still, Nancy is definitely relevant, with its simple and extensible programming model.