Sure, Blender has a built-in Game Engine but, don't let its primary functionality box you into just thinking about games. Think outside of the box, and you'll find that it's very useful for many different things. Mike Pan (aka mpan3) has done just that.
Mike has created several well-executed examples of how to use Blender's Game Engine in ways that will surely spark some ideas of your own. His examples range from a simple interactive 3D Earth-viewer that features high-resolution textures and moving clouds, to an interactive 3D Gallery that can load any image and display it on the canvas.
The best part is that these examples are .blend files so, you get to pick them apart to see how they were created!
1.) High Polygon-count models with different materials applied. (Marble, Pearl, Gold, Blue metal...) This is a demonstration of what you can do with just two layer of static texture and vertex lighting. (translation: even a graphic card such as the Geforce2/Radeon 7500 is capable of nice surface shading)
Techniques: High polygon models(source unknown, found in public domain), simple UV texture, reflective UV texture, vertex lighting, fake highlights with reflective UV textures.
2.) An Interactive 3D Gallery that can load any image and display it on the canvas. The lighting condition and the layout can be also customized. This demo runs on most PCs. Requires Blender 2.40.
3.) Stonehenge in the fog. A very moody scene with a high polygon count and minimal texture.
Techniques: Ground fog, add particles to scene, rotate camera around a fixed point.
4.) A simple interactive 3D earth viewer that features a high-resolution textures and moving clouds. Requires a modern graphi card to see the high-resolution textures. Texture courtesy of NASA. Requires Blender 2.40.
5.) Originally part of a benchmark suite, this tech demo features fake reflection, dynamic lights and reflective textures. Runs on most PCs. (car model source unknown, found in public domain). Requires Blender 2.40.
6.) A demostration on how to achieve hardware rendering (rendering on GPU) using Blender's internal game engine. A 20-second clip renders in a mere minute. A significant improvement over the traditional off-line rendering where a frame usually takes minutes, if not hours.
Techniques: render movie in realtime, capture screen using python, sky dome, using pre-defined ipo to drive animaitons, fog, alpha textured vegetations.
Important Note: Be sure to read the text in the Text Editor window for any available instructions.
Also, be sure to check out the other interesting things on Mike's website.
In what other creative ways can Blender's Game Engine be used?