Hi, LynxKite is a graph analytics application built on Apache Spark. (From very early on, like Spark 0.9.) We have talked about it on occasion on Spark Summits.
So I wanted to let you know that it's now open-source! https://github.com/lynxkite/lynxkite You should totally check it out if you work with graphs. But even if you only use SparkSQL you may find it a nice (graphical) environment for data exploration. We're going to do development completely in the open and with the community from now on, so any bug reports and pull requests are extremely welcome. Cheers, Daniel