Avogadro is an application purely for scientists and students that have to draw three-dimensional molecular compositions that showing a molecule from every conceivable angle and perspective.
It works across platforms and is used in computational chemistry, molecular modeling, bio informatics, material science and other related areas. The aim has been to make 3D molecular manipulation as easy as possible and even if your not a scientists, it's quite entertaining just creating your own different coloured structures that look good. This can be done simply by using the mouse buttons and dragging the molecules on their three axis. Probably the best aspect of this program for those with some coding knowledge is that it can be easily extended and developed via plugins. Avogadro is based on Open Babel according to the developers and in future, will also offer scripting options. The main problem you'll find is that like with many open source collaborations, it is prone to bugs and errors so it may crash at any time.
An excellent scientific tool that allows flexibility for those that want to develop plugins but is easy enough for anyone to use.
