Various flavors of Ubuntu 14.04 have come out today with their Trusty Tahr Alpha 2 spins.
Ubuntu itself still isn't doing alpha releases but instead encourages testing of the latest daily ISOs. For Edubuntu, Kubuntu, Ubuntu GNOME, Ubuntu Kylin, Xubuntu, and Ubuntu Cloud, there are alpha two images that were spun today for easy testing of these different flavors.
For those interested in testing these Ubuntu 14.04 derivatives you can find the announcement information via the ubuntu-devel-announce list
. The official release of Ubuntu 14.04 is coming in April and is a Long-Term Support (LTS) release.