The global home of Bitcoin Ninjas everywhere. If you're a Bitcoin Ninja, ping BlueMatt for a email/subdomain on bitcoin.ninja.
Public summaries of some wizardly thinking:

• ASICs and Decentralization FAQ
• Proof of Stake
• A Treatise on Altcoins (wip)
• There Is No 'From' Address
• Proving Your Bitcoin Reserves

Useful resources:

• #bitcoin-wizards logs here
• Sipa's hashrate statistics
• Gmaxwell's alt-ideas page

Papers of interest:

• Bitcoin systematization of knowledge