Gtkfortune is a small gtk2-perl frontend to the popular fortune program.
Gtkfortune reads from the plaintext %-seperated fortune database files, not the .dat files. You can create your own database by simply creating a text file with fortunes seperated by lone %'s on their own line. See the Notes file in the tarball for details.
The 'Information' and buttons that are seen in the screenshot are toggleable with the -b and -e flags, respectively. You can also specify your own fortune database file by passing it to gtkfortune (`gtkfortune /usr/share/fortune/calvin').
gtkfortune-0.1.tar.gz
The tarball contains a license file, a readme, the man page, the script itself, and the Notes file from the original fortune.