1. A computer-implemented method comprising: displaying a block diagram of a graphical program on a display of a computer system, wherein the block diagram includes at least a first plurality of interconnected nodes visually indicating functionality of the graphical program, wherein the first plurality of interconnected nodes includes a first node; associating a first event and a second plurality of interconnected nodes with the first node in response to user input, wherein said associating configures the first node to invoke execution of the second plurality of interconnected nodes in response to the first event being generated during execution of the graphical program, wherein the second plurality of interconnected nodes visually indicates functionality for responding to the first event; and executing the graphical program on the computer system, wherein executing the graphical program comprises: the first node receiving a notification that the first event was generated; and the first node invoking execution of the second plurality of interconnected nodes in response to the notification, wherein the second plurality of interconnected nodes executes to perform the functionality for responding to the first event.