1. A computer-readable memory medium containing contents that, when executed in response to a received event trigger, cause a computing device to automatically customize one or more applications for a particular user, by performing a method comprising: determining an event identifier of an event that caused the event trigger, a user identifier identifying the particular user, and a plurality of parameters; determining a plurality of applications that have been installed on the computing device, in whole or in part, and that are associated with the user identifier; retrieving a plurality of scripts associated with the determined event identifier and with the determined installed plurality of applications associated with the user identifier, each script corresponding to a corresponding application of the determined plurality of applications; and executing each retrieved script to automatically customize the corresponding applications, thereby customizing, for the particular user, the plurality of determined applications in response to the event.