For those who prefer the excitement of playing gaps, Bespoke conducted an interesting little study on Friday's gap behavior that's worth a look.
Gap studies seem to have become very popular lately.
Here are a few recent print articles on the topic:
June 2007 Active Trader magazine: One Day Jumps - by David Bukey
August 2007 Active Trader: Opening Gap Trader - staff writers
January 2007 Active Trader: Gauging Gap Opportunities - by David Bukey
July 2007 Technical Analysis of Stocks & Commodities magazine:Laps and Gaps - Larry Connors
Also in July 2007 TASC: Premarket Prediction- V. Wang