OpenOffice is a great program suite but the default OpenOffice theme is a bit boring. To alleviate this you can tell OpenOffice to use your current GTK theme.
The best way that I've found to enable GTK themes for OpenOffice is as follows:
1. Open up the file /opt/openoffice.org3/program/soffice in your favorite text editor.
NOTE: soffice is just an ASCII text script with no binary code so you will have no issues opening it in your text editor.
2. Add the following line to the soffice file somewhere near the top: export OOO_FORCE_DESKTOP="gnome"
NOTE: I put it right after the "export SAL_ENABLE_FILE_LOCKING" line.
3. Now save the file and you're done.
NOTE: This is all assuming that you already have a GTK theme defined via the .gtkrc-2.0 file in your home dir, or some other method.
Some people say that you should put this line in your .xsession file or in /etc/openoffice file instead of directly into the OpenOffice script, but for me this was the only way to make sure it sticks and that GTK themes work 100% of the time. Keep in mind that your install of OpenOffice may not be in the /opt dir and that the "3" at the end of /opt/openoffice.org3 will only be there if you're using OpenOffice version 3.