The latest Gant distribution downloads are available:
1.9.7 8 Source
1.9.7 Binary, compiled for use with Groovy 1.7.10 installation
1.9.7 8 Binary, compiled for use with Groovy 1.8.4 6 installation
1.9.7 8 Binary, compiled for use with Groovy 2.0.0 -beta-1 installation
1.9.7 8 Binary, standalone installation
Installation of any of the binary distributions is simply a matter of extracting the distribution to the desired location. A directory gant-1.9.7 8 will be created.
The jars have been uploaded to the Codehaus Maven repository (which then gets synced to the central Maven repository), the groupId is org.codehaus.gant, the artifactId is one of gant_groovy1.7, gant_groovy1.8, gant_groovy2.0 (indicating which Groovy version the artefact was compiled against), and the version is 1.9.78.
Earlier distributions are available at http://dist.codehaus.org/gant/distributions.
If you want to stay more up to date but don't want to install from source, there is the following deb file which creates a stand-alone installation of Gant with all the dependencies it needs, including Groovy 12.80.40:
Gant 1.9.7 8 standalone
The page https://admin.fedoraproject.org/pkgdb/acls/name/gant details all the Gant packages for the various Fedora versions. Sadly it seems they haven't progressed beyond 1.8.1. If there are any Fedora users out there who can contact the Fedora packagers to get them to update to the latest version that would be good.