Quantcast File System (QFS) is a high-performance, fault-tolerant, distributed file system developed to support MapReduce processing, or other applications reading and writing large files sequentially.

Atom Hopper is an open source ATOMPub server for accessing, processing and aggregating ATOM entries. Atom Hopper was designed to make it easy to build both generalized and specialized persistence mechanisms for ATOM XML data, based on the ATOM Syndication Format and the ATOM Publishing Protocol.

oVirt manages virtual machines, storage and virtualized networks.

HTCondor is a specialized workload management system for compute-intensive jobs. Like other full-featured batch systems, HTCondor provides a job queueing mechanism, scheduling policy, priority scheme, resource monitoring, and resource management. Users submit their serial or parallel jobs to HTCondor, HTCondor places them into a queue, chooses when and where to run the jobs based upon a policy, carefully monitors their progress, and ultimately informs the user upon completion.

Apache Mesos is a cluster manager that provides efficient resource isolation and sharing across distributed applications, or frameworks. It can run Hadoop, MPI, Hypertable, Spark (a new framework for low-latency interactive and iterative jobs), and other applications.

Gitblit is an open-source, pure Java stack for managing, viewing, and serving Git repositories.
It's designed primarily as a tool for small workgroups who want to host centralized repositories.

Graphite is a highly scalable real-time graphing system. As a user, you write an application that collects numeric time-series data that you are interested in graphing, and send it to Graphite's processing backend, carbon, which stores the data in Graphite's specialized database. The data can then be visualized through graphite's web interfaces.

Preboot is a super awesome pack of mixins and variables to be used in conjunction with LESS, a CSS preprocessor for faster and easier web development.