Market Related Google Finance Enter a ticker symbol to get a feel for things. It's in Beta right now, but it looks great to me.
Magic Formula Investing This is a sight that lets you screen for stocks according to the "magic formula" from Joel Greenblatt's "The Little Book That Beats the Market". The site is free, but you do need to register.
Max-Pain The idea is that since the vast majority of options expire worthless, the price at which the maximum number of options would expire worthless will often serve as a kind of magnet for a stock or index as option expiry approaches. This site provides the Max-Pain point for the OEX, SPX, QQQQ, and about 20 of the more heavily traded stocks.
SPDR Index Correlation Enter a ticker symbol (it doesn't have to be a SPDR) and you will see the instrument's correlation with various SPDRs over a 6 month, 1 year, or 3 year period, as well as those stocks with which it is most positively and negatively correlated.
Not Market Related The Memory Hole "The Memory Hole exists to preserve and spread material that is in danger of being lost, is hard to find, or is not widely known." Lots of interesting stuff here, some obtained through Freedom of Information Act requests.
Gridskipper The urban travel guide, specializing in the offbeat.
The Sidis Archives A collection of material by and about one of the most brilliant people to ever grace the planet. I'd highly recommed Amy Wallace's book "The Prodigy" to anyone interested in the life of the remarkable William Sidis. It's full of great anecdotes about Sidis ( he taught himself Latin when he was 4 so he could read the Gallic Wars to his father as a birthday present) as well as his Russian immigrant parents.The story of his mother propping up Euclid's Elements by the kitchen sink so she could study it while washing dishes or how his father obtained a much needed winter coat by providing a philosophical tailor with lessons on Spinoza in lieu of cash are two that come to mind.
