Ubuntu has a nice configuration editor (very advanced, and possibly dangerous) for Gnome that is installed by default (but hidden from the menu by default).
This configuration editor can be run through the command (Alt-F2): gconf-editor
Or, you can right-click the Applications menu, click Edit Menus and then you can see the lists of things in the Applications Menu (some may be disabled from appearing by default when they are unchecked, others you can uncheck if you don't want to see them). Click the System Tools menu (in the left-hand column) and then check Configuration Editor (in the right-hand column). There are many apps that you may not have heard about, so you can check the boxes and try out the apps.
As I said before, you may want to be careful with what you do in the Configuration Editor as it could damage your user interface if you do something silly.
