Where to start, a juicy one!

Apple of my eye ~ somebody I really like (common in songs, but not everyday)

Bite the apple ~ a reference to the garden of Eden, and original sin (not common) or even Cinderella (poisoned to sleep with a drugged apple)

The big apple = New York City

Apple computers, of course....

How do you like them apples? = what do you think about the punishment you have been given?

That chair is made of apple (=apple tree wood)

Those are just some off the top of my head.