Synergy is a plugin that can create random animations based on a variety of parameters.
At its core, Synergy has the notion of steps and modifiers. Each step can contain one or more modifiers, which are used to drive certain parameters such as forces on a rigidbody or morph values. A step has a duration, which is used to synchronise the modifiers. Once the duration has elapsed, Synergy moves on to the next step.
There is a simple example in Saves/scene/SynergyExamples. It runs for about a minute before looping.
See Getting started on the wiki [github.com] for more information.
Example of a rigidbody modifier: