GTetrinet 0.7.10 is out. This release fixes a security hole (CVE-2006-3125), so you're advised to update ASAP.
The last release was assembled during UbuntuDownUnder, back in April 2005, which is a good indication about GTetrinet's development health. If you're interested in writing new features or fixing the many bugs in GTetrinet, please consider joining the mailing list. GTetrinet really needs your help!
Debian binaries are on the way to unstable; Ubuntu will hopefully suck them up soonish. Get the hot tarball from the GNOME FTP mirrors.