Key to the OWASP O2 Platform environment is its ability to quickly write scripts and mini-tools. In fact I took that to such a level, that I now write O2 in O2 (i.e. without using VisualStudio).
At core of O2 Scripting there is an .NET development environment (by default in C# but any .NET language is supported), and since O2 is starting to be use independently by developers, I separated the O2 core into a new API which I'm calling FluentSharp (see CodePlex project http://fluentsharp.codeplex.com/):
The main http://fluentsharp.codeplex.com/ page contains an example of how this API works and the reasoning behind the 'Fluent' concept.
I expect developers to embrace this API since it can improve their productivity, while creating smaller and more readable code. The first place to start is to use FluentSharp to build Unit-Tests and Integration-Tests (which once created can be extended into Security Tests using O2 :) )