4. The non-transitory computer-readable medium of claim 1 , wherein the instructions further comprise instructions to: create a state definition responsive to the associating of the one or more triggers with the personalized avatar, the state definition specifying the one or more triggers and referencing the personalized avatar.
1. A non-transitory computer readable medium encoded with a computer program, the program comprising instructions executable by a data processing apparatus, the instructions comprising instructions to: receive one or more inputs creating a personalized avatar; receive one or more inputs creating one or more triggers; associate the one or more triggers with the personalized avatar; detect an occurrence of one or more of the triggers; and display, in accordance with the detected occurrence, the personalized avatar, wherein creating a personalized avatar comprises modifying an existing avatar based, at least in part, on a composite of previously created avatars.