From the Quest3D site:

Version 4.0 of Quest3D® is now available from Quest3D resellers and the Quest3D website.

With the release of Quest3D 4.0, Act-3D™ B.V. lifts its flagship to an even higher quality level of real-time 3D application development. New functionality contains real-time support for COLLADA, Newton Game Dynamics, Advanced Weather Simulation, 3D GUI Support and a fully Object-Oriented development model.

The new release is a giant leap forward in real-time 3D software development. High-end 3D software projects, such as 3D architecture visualizations, product and design presentations games and training simulators benefit from the newly supported technologies in Quest3D.

Audiosurf is doing really well, you could say it’s steaming, you may must have spotted it on sites like IGF, youtube, Gamasutra, and Gamespot! And as from the 15th of February available from the steam network, for just $9.95!

A review from Voodoo Extreme concluding with a 4.5 out of 5 rating!

The Conclusion

The Good:

+ Addictive, score-based gameplay
+ Excellent visuals and beat-matching
+ Worldwide leaderboards with friend integration
+ Achievements
+ Cheat reporting system

The Bad:

- Menu music that cannot be muted
- Windowed mode fussy about resolutions (manually drag to circumvent issue)
- Website services currently offline
- Dull gameplay on slow songs
- No Mono-only scoreboards
- Your eyes will melt on Elite difficulty