15. A computer-readable storage medium having stored thereon computer-executable instructions that, if executed by a computing device, cause the computing device to perform operations for controlling a rendering engine, the operations comprising: receiving commands at a computer specifying one or more character actions for a computer-modeled character displayed at the computer, wherein the commands are from a content provider at a first location and the computer is at a second location remote from the first location, wherein the commands comprise predetermined instructions in a control script for the one or more character actions and an electronic representation of human speech; and wherein one or more of the predetermined instructions include a specified duration; and animating lip movement of the computer-modeled character displayed at the computer at the second location, wherein the animating is performed according to the predetermined instructions in the control script, wherein the animating comprises synchronizing an audio representation of a human speech with the animated lip movement of the computer modeled character, and wherein the synchronizing is performed by maintaining a constant playback rate by indicating a start time and duration time corresponding to a set of one or more of the predetermined instructions in the control script such that each resulting animation that comprises a pre-computed lip movement fits into the corresponding specified duration.
16. The computer-readable storage medium of claim 15 wherein default character actions are automatically specified by the rendering engine at the computer at the second location if omitted by the control script, and wherein animating lip movement of the computer-modeled character comprises animating lip movement of the computer-modeled character based, at least in part, on default actions from the rendering engine of the computer at the second location.