Usage tip: its vs. it's--with bonus visual aid!

So you think you've figured out how to use the apostrophe. The apostrophe is used to indicate possession and to take the place of missing letters in a contraction. No problem! You've got it down.

And then, along comes...its.

English being English, you know there has to be an exception to every rule (and several exceptions to each exception, too, in most cases). Well, its is it.

Use its to indicate that it owns something. Use it's to replace it is.

Correct:
The dog carried its bone to its den.
It's a nice day for a walk.
It's got a big scar on the back of its head.
It's a zombie! Run!

Incorrect:
The bird used newspaper in it's nest.
Its too late to watch TV tonight.
Its carrying its baby in it's mouth.
Its after your brains!

And just when I thought I had finished with The New Yorker ad fail, I get this week's issue and see this: