"Legos" always sounded weird to me. Interestingly enough, LEGO used to have this on their site:
“The word LEGO is a brand name, and is very special to all of us in the LEGO Group Companies. We would sincerely like your help in keeping it special. Please always refer to our products as “LEGO bricks or toys” and not “LEGOS.” By doing so, you will be helping to protect and preserve a brand of which we are very proud, and that stands for quality the world over. Thank you!”
“The word LEGO is a brand name, and is very special to all of us in the LEGO Group Companies. We would sincerely like your help in keeping it special. Please always refer to our products as “LEGO bricks or toys” and not “LEGOS.” By doing so, you will be helping to protect and preserve a brand of which we are very proud, and that stands for quality the world over. Thank you!”