Here is the list of interesting projects associated with big data ecosystem.
Ambari: The Apache Ambari project is aimed at making Hadoop management simpler
by developing software for provisioning, managing, and monitoring Apache
Hadoop clusters. Ambari provides an intuitive, easy-to-use Hadoop
management web UI backed by its RESTful APIs. [Apache]
Avro: Data serialization engine for distributed/big data. [Apache]
BigTable: Google's non-relational system that includes terabytes of memory and petabytes of storage which can deal with millions of reads or writes per second.[Google]
Chubby: Google's lock service for loosely coupled. [Google]