us

Me and at least one other person, excluding the person(s) being addressed. (exclusive us.)

Don't treat us like idiots.

Me and at least one other person, including the person(s) being addressed. (inclusive us.)

Let's ask him if he'll give us a lift.

Forasmuch as many have taken in hand to set forth in order a declaration of those things which are most surely believed among us...

We, used in the same circumstances where "me" would be used instead of "I", e.g. for the pronoun in isolation or as the complement of the copula

Who's there? — Us. (or) — It's us.

Who's going to go? — Us. We'll go.

Any entity that the speaker is a part of or identifies with, such as place of employment or education, nation, region, language, etc.

It's not true that the rest of Europe hates us.

I went to watch my favourite team play Real Madrid, but they thrashed us 5-0.

People in general.

Grief ages us.

Designates the speaker(s)/writer(s) as constituting or belonging to the stated category of people (objective case).

It's not good enough for us teachers.

Designates the speaker(s)/writer(s) as constituting or belonging to the stated category of people (subjective case).

Us gays and lesbians in here got a reason to be bitching about the conditions.

Our.

We'll have to throw us food out.

The relationship (usually romantic) between the speaker and listener or some other unspecified person.

There is no us.

Us is the best thing that's ever happened to me.