How can I get more chocolate?

I want to maximize Stinky's ability to collect coins while I'm not using Plants Vs. Zombies, and that means giving him regular feedings of chocolate. How can I maximize my chocolate harvest while actually playing the game?

I'm using the iOS / iPad version - in case it matters.

The PvZ wiki has a bunch of useful info on Chocolate. Here's how you get more chocolate in most (all?) versions of the game:

Randomly from Killing Zombies.
Occasionally eating a Brain in I, Zombie.
A streak of 3 in I, Zombie Endless.
A streak of 10 in Vasebreaker Endless.
Sometimes after a Grave Buster eats a Grave during a Night level.

^{(from the wiki)}

The puzzle game mode methods seem to be a much more reliable method of earning chocolate (and rare plants) than just killing zombies in the story mode.

Note that you can only hold 10 chocolates at once, so once you have 10 in stock keep using them. For those who don't know, Chocolate won't spawn until you have Stinky the Snail.

If you have a full 10 and need to use a couple you can also give them plants that are already producing coins in the zen garden. It will double their coin output for an hour.