  This paper introduces a new empirical model for the rotational evolution of
Sun-like stars -- those with surface convection zones and non-convective
interior regions. Previous models do not match the morphology of observed
(rotation period)-color diagrams, notably the existence of a relatively
long-lived "C-sequence" of fast rotators first identified by Barnes(2003). This
failure motivates the Metastable Dynamo Model (MDM) described here. The MDM
posits that stars are born with their magnetic dynamos operating in a mode that
couples very weakly to the stellar wind, so their (initially very short)
rotation periods at first change little with time. At some point, this mode
spontaneously and randomly changes to a strongly-coupled mode, the transition
occurring with a mass-dependent lifetime that is of order 100 MYr. I show that
with this assumption, one can obtain good fits to observations of young
clusters, particularly for ages of 150 MYr to 200 MYr. Previous models and the
MDM both give qualitative agreement with the morphology of the slower-rotating
"I-sequence" stars, but none of them have been shown to accurately reproduce
the stellar-mass-dependent evolution of the I-sequence stars, especially for
clusters older than a few hundred MYr. I discuss observational experiments that
can test aspects of the MDM, and speculate that the physics underlying the MDM
may be related to other situations described in the literature, in which
stellar dynamos may have a multi-modal character.
