Apache Mesos and it's ecosystem (Apache Aurora, Marathon, Apache Myriad, Chronos etc.) has been the most kind, supportive and talented ecosystem of open-source projects.
It's a community of individuals who are very talented, patient, helpful and inviting.
Disclaimer: I work at Mesosphere, and one of the co-founders of Apache Myriad.
I think Cloud vendors should come forward proactively, and frame a set of standards for interoperability in the cloud. An inspiration could be taken from the Virtulization industry, that came up with OVF (Open Virtualization Format).
I (Mohit Soni) and my 2 friends (Shashank Shekhar and Kalyan Chakravarthy) are working on Flare (A True WebOS). We were finalists in Google Product Prodigy 2009. Very soon we'll be launching Flare as a service.