It may be a takeover target. one analyst called it, quote, one of the biggest bombshells in recent history. the average 30-year fixed mortgage rate has matched its record low. today is quadruple witching day. equity options expire, as do stock index futures, stock index options and individual stock futures. the stock to watch today is zinga. its ipo priced at $10 a share. and finally, the $116 million taken in by christie's elizabeth taylor jewelry auction makes it the most valuable private jewel collection ever sold. coming up, another serious concussion injury in hockey. and sports mix...