The Trinity Desktop hasn't seen a new release since November of 2011 with Trinity v3.5.13, but the project remains active. In mid-June of this year there was a news update concerning a "R14" release (v3.5.14). "TDE development is still actively progressing towards the R14 release. As you may be aware, the TDE project has decided to release when ready instead of following a strict release schedule; this decision was made to increase the overall quality of the TDE system and to make it more attractive for use in enterprise environments. Over the past few weeks many critical bugs have been quashed and we are tentatively rescheduling R14 release for Fall 2012."
Beyond a news announcement they hope to have a new release around this fall, the Trinity Desktop patch-flow continues to be quite high. As shown from the patches page, there continues to be new KDE/Trinity patches hitting about daily to the 3.5 code-base. A majority of these patches come from Timothy Pearson, the original forker of KDE 3.5 into Trinity, along with a few other developers that are interested in keeping KDE 3.5 alive. There's also "community-supported requests for feature enhancements" on the CRFE page, but that donation-driven work isn't very active at all.
In terms of the mailing lists, their trinity-users and trinity-announce lists haven't been active in months but the trinity-devel list for coordinating development does continue to be active.
For those interested in trying out Trinity to relive the old KDE experience, packages continue to be abailable for recent releases of Debian, Ubuntu, Red Hat, Fedora, and Slackware via TrinityDesktop.org.
Speaking of desktops, new desktop environment / window manager benchmarks are coming from Ubuntu 12.10 and even the new Unity/Compiz remains slow.