Now we have ubuntu 15.10 released and if you want to know the next ubuntu release name then here it is Ubuntu 16.04 LTS to Be Codenamed Xenial Xerus.This was announced on 21st October 2015 by Mark Shuttleworth.
From Mark Shuttleworth Original Blog Post
"What fortunate timing that our next LTS should be X, because “xenial” means “friendly relations between hosts and guests”, and given all the amazing work going into LXD and KVM for Ubuntu OpenStack, and beyond that the interoperability of Ubuntu OpenStack with hypervisors of all sorts, it seems like a perfect fit.
And Xerus, the African ground squirrels, are among the most social animals in my home country. They thrive in the desert, they live in small, agile, social groups that get along unusually well with their neighbours (for most mammals, neighbours are a source of bloody competition, for Xerus, hey, collaboration is cool). They are fast, feisty, friendly and known for their enormous… courage. That sounds just about right. With great… courage… comes great opportunity!"