Another impulse based 2D physics engine written in pure .NET. Has an excellent API and can be integrated in a matter of minutes.

A 2D physics engine completely written in C#

Microsoft's free DirectX SDK, used to access 3D accelerators, sound cards and input devices through a unified interface. Includes Managed DirectX for .NET 1.1 as well as the new Managed DirectX for .NET 2.0.

Portable .NET bindings for most of the libraries popular in game development, including DevIL, OpenGL, SDL, Cg, ODE and OpenAL. Saves you from the work of writing custom wrappers and updating them on each and every .NET platform, though you will still have to cope with the procedural API these libraries provide.

A complete C# rewrite of the well-known Ogre 3D rendering engine. This is a high-level engine which provides complete abstraction from the 3D API, supports both OpenGL and DirectX, contains a well-designed scene graph model and understands CG for complex shaders. In short, this is a very good component for the rapid development of real-time 3D applications in .NET.

Purple# is a game engine written in C# from scratch. Besides being a 3D engine, this project also integrates audio playback, input device management and simple GUI capabilities.

Open source dynamics simulation library. This is the most widely used library for realistic physics simulation in games that can't afford the expensive Havok engine. ODE has a large developer community and is, if correctly used, able to deliver believable and fast physics.

Closed source dynamics simulation library for games. Less known, but in many cases easier to implement and get right than the complex ODE engine.

A closed source dynamics simulation library for games. This library is said to provide better results than many of the other libraries out there and is very easy to integrate, too. On the other hand, it's not available for free.

Ageia's PhysX SDK (previously known as Novodex) is a direct competitor to the widely used Havok physics engine in commercial AAA-titles. Ageia's SDK is available for free and besides to full range of rigid body physics, it also has some neat features like fluid simulation. Using this SDK also enables you to harness Ageia's PhysX hardware physics accelerator.

Bullet is a project by an ex havok employee. It has developed into a real physics engine that offers continuous collision detection (in contrast to most of the other physics engines which let objects penetrate each other and then try to compensate by moving the objects around) and a solid set of rigid body physics functions.

An upcomer between the currently established physics solutions. This library claims to do swept collision detection, meaning that even the fastest moving objects (bullets for example) would not be able to 'tunnel' through other objects in low frame-rate situations.

A thin wrapper around Tao.Ode to provide ODE with more .NET-like interface in .NET languages such as C#.

Short for "Open Physics Abstraction Layer", this class library is a high-level abstraction layer for all kinds of physics engines. Using this library, you can switch between different physics engines, such as ODE or Ageia PhysX, without even touching your code. Also has a multitude of neat features such as motors and sensors that greatly ease the creation of physics-dependant code.

Complete C# rewrite of Opal (Open Physics Abstraction Layer). Just as the original opal, this library abstracts your code from the underlying physics engine, enabling you to switch between various physics engines such as Bullet or Ageia PhysX without even touching your code. Contains a lot of neat helpers such as sensors and motors that greatly ease the development of physics-dependent code.