Apache Flink (Incubating): Flink is an open source system for expressive, declarative, fast, and efficient data analysis. Stratosphere combines the scalability and programming flexibility of distributed MapReduce-like platforms with the efficiency, out-of-core execution, and query optimization capabilities found in parallel databases.  Flink was originally known as Stratosphere when it entered the Incubator.
Incubation: 2014-04 to 2014-12 (graduated)