Heres a little 3d demo I made over the weekend using DirectX 9.
There are 20+ ships flying around using Artificial Intelligence for their steering behavior. Ships can have a wandering or chasing behavior. The chasing ships fire seeker rockets when in range. This was done by implementing a state machine for the ships.
The explosion of earth is done using a particle system using DirectX Point Sprites with physics simulation and an animated explosion texture (billboarded). The explosion has more than 5K individual particles. All the physics calculations are done in the graphics card side using programmable shaders with HLSL.
The 3d Meshes are from Google 3D Warehouse and exported to .X files using a plugin available online.
The demo was coded by myself over a period of 2 days of strong coding.