I don't care about the trademarks, but as a Brit 'Legos' always sounds wrong, like "I'm playing with my sheeps".

On the other hand, don't we in the UK always talk about "maths" rather than "math".

That's a different matter: how does one contract a plural - but the plural is still the same:

- Math is short for mathematics, not for mathematic, which isn't a word (try looking up 'mathematic' sometime).

- Maths is also short for mathematics.

"mathematic (n.) - late 14c. as singular noun, replaced by early 17c. by mathematics, from Latin mathematica (plural), from Greek mathematike tekhne "mathematical science," feminine singular of mathematikos (adj.) ..."

http://etymonline.com/index.php?term=mathematic

The obvious comparison is to "physics" which is short for "physical sciences" IIRC.

Was mathematics once referred to as "the mathematical arts" or something?

(A similar way to appear very uncool is to walk into a record shop and proclaim, "look at all these vinyls!")

It isn't "short for" anything. This is just a normal suffix for fields of study: Physics, mechanics, politics, statistics, optics, ethics, linguistics, and so on.

Etymologically it is a plural suffix, but in modern English it is singular.

http://dictionary.reference.com/browse/-ics

Cambridge University has a 'Centre for Mathematical Sciences', housing both the departments for pure and applied maths.

You're not contracting a plural. Mathematics is singular. "Mathematics IS a field of study", not "Mathematics are fields of studies". There aren't "3 mathematics".

A history of math vs maths: http://m.youtube.com/watch?v=SbZCECvoaTA

Etymologically mathematics is a plural, as another poster notes. There are many smaller topics involved in mathematics: geometry, trig, calculus, etc. Much in the same way as mechanics, optics, politics, acoustics, etc (as a different poster mentions).

'maths' is not plural, it's a contraction of 'mathematics'.

British people don't call them lego because of trademark issues, we call them that because we consider it to be a mass noun.

Canadians too. Not sure why.

Trying to get people not to use the obvious plural is silly, but the insistance on all caps bothers me even more. It's right up there with Yahoo's exclamation mark. The convention is that everyone will call you, usually, by the name you choose, but demanding that other people use your preferred typographical novelty is lame.

This may be a regional thing? I've always used "Lego" as a mass noun as in "I'm playing with Lego". The pluralization "Legos" sounds weird to me.

As someone who spent a ludicrous amount of time during my childhood playing with Legos and always referring to them as such to friends and family, I really don't appreciate this "request". I'm quick to correct my ways when I realize that I've been mispronouncing or misusing a word, but when we're talking about a children's toy brand (however cool it may be), let's just all take it easy.

The title for this link needs to be fixed. It's a question with some answers, and very few of the answers reflect the position stated in the title.

I have never played with only one lego therefore I refer to them as legos because I play with more than one.

But a single brick isn't called a lego, it's called a LEGO brick (or part). You have never played with one LEGO brick, you have played with LEGO bricks.

Would you build a house out of house bricks or out of houses?

Ask any kid from age 4-10 if they have ever called legos "lego bricks"

Conversely: I have never fished for only one fish therefore I refer to them as 'fishes' because I fish for more than one.

Fish are not interlocking pieces that connect together to form larger objects.

Except if your surname is 'Escher'.

Yes. That is correct.