At Gillette stadium (where the Patriots play their home games) there is this odd looking silver and yellow logo on the side of the 50 yard line. It looks like three gray rectangles, with yellow vertical lines on top, when viewed from the nearest sideline. What is it? What does it mean? Why is it there?

It's a very stylized bridge and lighthouse. This is from the official website about the stadium: I think it's describing the logo:

These features include the bridge and 12-story high lighthouse that will sit atop the Bank of America entrance and welcome visitors to the stadium.

yea its wierd it looks like a ship shooting out lightning bolt,s what is that?

its actually an ancient indian symbol that means stadium of cheaters

It's actually some sort of logo for Gillette. Go to the website for the stadium and you will see it. What it means and where it came from, I can't answer.