Pity poor Mimas! The "that's no moon" moon of Saturn ought to be as famous as its sibling Enceladus. All other things being equal, Mimas should be more strongly tidally heated, but this is clearly not the case. This talk will review the latest Cassini findings for both moons, including the astonishing heat flow coming from Enceladus' south pole. It turns out that Mimas' lack of geologic activity is no surprise — the real question is how does Enceladus support its heat flow, active tectonics, and erupting plumes?