• the "Click Fast" button that makes use of the Gtk::timeout_add() and Gtk::timeout_remove() functions
• a Desktop Widget that can be used for useful information you want to keep in view
• visualProxy - an HTTP proxy server and transmit HTTP proxy requests from a WWW user agent to an other proxy or directly to a server. It displays requests graphically and update information on the fly on a detailed list with many fields columns.

Check out their apps and code snippets sections for more examples like these.

• CommandWidget - a terminal like widget for php-gtk
• Dial widget - a graphical widget to display an analog value
• ScrollingLabel - a funny label widget with scrolling capabilities
• Timer class : simplifying gtk::timeout_add

Keep an eye on the Code Snippets section of the PHP-GTK website for more helpful tips and tricks.