How to grow plants from the foods you eat:

Apple tree - grow your own apple tree from an apple seed

Avocado - How to grow an avocado tree from a pit

Carrot fun - grow a carrot plant from a carrot top

Celery - grow celery

Scallions - grow scallions indefinitely!

Potatoes - grow them in trenches or towers and another version of growing in towers

Pumpkin - add soil to the pumpkin and watch nature take place!

Romaine Lettuce - same technique as celery

want to read more about it?  I found a book on amazon about it
Don't Throw It, Grow It!: 68 windowsill plants from kitchen scraps