Dynace is a portable extension to the C language which adds object-oriented facilities, including classes with multiple-inheritance, a meta-object protocol, dynamic dispatching via generic functions, a garbage collector, threads, and an extensive class library, including an optional GUI library. It has complete documentation and a tutorial.
Concerted is a highly scalable multivariate in-memory data storage library. It has built in support for multivariate queries and performs well over many styles of workloads. The data is read and stored in various data structures, and the data from data structures written to disk. It is fully ACID compliant, has APIs that abstract details from the user, and provides an easy to use interface. Many different types of indexes are provided along with various systems that provide access for data analytics.
Aurora-Sim is the next generation of the OpenSimulator Project. It allows you to run a large scale operation and extend it as needed, while still having many features available for your use. The architecture is designed to be as flexible as possible so that third parties can create modules by plugging into the modular design. It is cross-platform compatible by using the .NET framework and Mono. Most importantly, it is a community based project consisting of individuals with a variety of talents (technical and non-technical) and has been developed with an emphasis on security, speed, and performance.