An official update to the Sauerbraten game atop "Cube Engine 2" is imminent while work on the Tesseract project -- basically a modernized and more visually advanced version of the open-source Cube Engine 2 -- is still in development.
Per this Cube Engine forum thread, there's plans to have a November update. Those release plans were drawn at the end of October when it was called for Sauerbraten contributors to finish any maps they have and to place them into the SVN repository. The end of November is quickly approaching but there's no sign of a release yet. The release is coming though and the latest commit to their SourceForge SVN repository was earlier today.
The last official Sauerbraten release was two years ago. For those not familiar with this open-source game and engine, there's screenshots and more information from this 2009 Phoronix review.
Meanwhile, Tesseract is still in development too. Tesseract is an advanced version of the Cube Engine 2 that was announced earlier this year. Tesseract introduces new features like HDR rendering, deferred shading, omni-direction point-light shadow-maps, refractive alpha cubes, refractive glass materials, and other visual enhancements. The Tesseract Git repository is still seeing new commits every few days although there's no sign of an imminent release on that front.
Embedded below is a new demo powered by Tesseract as of earlier this month.
Another game available that's based off of Cube 2 is Red Eclipse with its most recent release being from September.