If you're familiar with Rhino you probably know Grasshopper, a plugin for parametric object creation. Sverchok (Russian for Cricket) is a new Blender add-on which aims to achieve the same functionality for Blender.
Sverchok is a node-based generative addon for creating parametric forms in Blender. Those familiar with Houdini or Rhinoceros 3D might know the visual scripting language Grasshopper, which Sverchok has been inspired by. Using a similar node based visual programming method, Ukrainian/Russian artists/programmers Nikita and Alexander have brought this functionality to Blender users.
This is the first implementation of the addon and there are limits due to the small NURBS Library found in Blender right now and the Python API places it's own restrictions on speed of development, but Nikita says, “Future implementations of Sverchok (Cricket) will include nodes for math, expressions, finding specific edges, vertices, polygons, evaluate points on a spline, and ability to make node chains, etc.”
So if you are interested in architectural tools and/or generative arts and how a node based approach to creating parametric 3D objects works, the Cricket is a great new addition to Blender. Try it out and give the guys feedback over at BlenderArtists.
Alexander Nodovizin (who recently created the Grid Fill Manager addon) and Nikita Gorodetskiy (Nikitron tools addon) are in working team.