This document discusses how monkey testing can complement GUI testing scripts. It describes how monkey testing generates tests at runtime without scripts, testing randomly to find errors anywhere in the system. Monkey testing finds different failures than scripts and covers more code. The document also introduces TESTAR, an open source monkey testing tool that detects GUI states, derives possible actions, selects actions randomly or through machine learning, executes actions, and checks for failures through implicit oracles. TESTAR can be enhanced with capabilities like learning models of the application to systematically explore the GUI.