Loads of fun. Check it out.
What's YOUR best score? First one I got was 666 (YES), second one was around 800, then I downloaded it to my FTP (<3 SSH + wget) and decided to share with you. I'll play more tomorrow. ^^
http://www.newbyproductions.net/images/gridgame.swf
After I figured out what to do, I got about 800.
[EDIT]: (http://www.quikness.com/grid.jpg)