Afaik (ask Samuel Thibault) Hurd development still continues, but slowly, encountering some problems because of bad interfaces (I think I heard about MIG and Mach yes) and POSIX requirements. But it (since recently, only some years) features x86_64 and USB support, which are new things. It also support the X Window System. What it principally lacks yet (beside general architecture redesign) are more architectures, sound, and wireless networking (but I heard there was work for this to make “glue code” so that to support all the Linux’s wireless drivers without rewriting them).
So it’s slow, unfinished, but not non-working or stopped at all. It’s just a non-priority, mainly developped on the free-time of 1-2 people (mainly youpi and braurn iirc)… But help would be appreciated I guess (the main problem, as I-forgot-which-one-of-those did put it very well: sufficiently skilled people lack sufficient time, and people with enough time lack sufficient skills :/)