An advanced public domain version of csh.
While there is a binary of this in /usr/local/contrib/bin, I would not recommend that you use this path for your shell. Having a shell on an NFS server just seems a little risky to me. So, I recommend that you copy the contrib binary to either /bin or /usr/local/bin, on your local disk, then change your default shell to this.
If you do this, and use scologin to log in, you will also need to copy the file Xsession-tcsh from the tcsh source directory to /usr/lib/X11/scologin, then edit the first line of this script to point to the location in which you installed tcsh.