[AgentME]

Stakers take act like miners, but instead of staking computation time through proof-of-work, they stake an amount of cryptocurrency which gets burned if they ever double-vote (and maybe if they vote for the losing chain, etc, depending on the scheme).

It's not very obvious how exactly a proof-of-stake scheme should work though. Many past attempts have been pretty flawed. I'm excited to watch Ethereum's progress in this area.