Polygonising a scalar field
May 1997 - Paul Bourke
This article describes the Marching Cubes algorithm in detail. It also comes with source code.
Polygonising a Scalar Field Using Tetrahedrons
June 1997 - Paul Bourke
This article describes a technique closely related to Marching Cubes, but it instead divides each cube into 6 tetrahedrons and compute the iso-surface using those instead.
The Blobs Go Marching Two by Two
November 1999 - Jeff Lander
This article explains metaballs and how they can be rendered using marching tetraeders, a cousing to the marching cubes algorithm. It also talks a little about the patent on the marching cubes algorithm.
Fast Polygonization of Implicit Surfaces
Frédéric Triquet, Philippe Meseure, Christophe Chaillou
A very good article on how to improve the performance of metaballs for use in realtime animation.
Component-based Polygonal Approximation of Soft Objects
2001 - Kuyng-Ha Min, In-Kwon Lee, Chan-Mo Park
A novel approach to polygonizing implicit surfaces such as metaballs. The algorithm uses an approximation of the control objects that is then subdivided to desired resolution.
April 2001 - Andreas Jönsson
This article explains a surface walking algorithm that can be used to increase the speed of rendering metaballs a lot.