add game hacking instructions

Callbacks/WarmUp.md

@@ -5,3 +5,22 @@ In JavaScript, [functions](https://javascript.info/function-basics) are a way to
 [Click here to play the Function game.](https://embed.mangahigh.com/bubblefunction?locale=en-us&guestMode=false)
 
 The goal is to use the proper function to match the input bubbles to the bubbles on the field already. Good luck!
+
+## BONUS: Hack the Game
+As it is, the game is setup to automatically stop working after three minutes. If this happens, you'll lose all your progress! Luckily, there is a way to hack it so that you can keep playing indefinitely 🐱‍💻😎
+
+The hacking code looks like this:
+
+```js
+Play.showLoggedOutMessage = () => { console.log("HEY!") };
+```
+
+Here's what you should do:
+
+1. Reload the page
+1. Open the JavaScript console (in Chrome with `Ctrl`+`Shift`+`J`)
+1. Copy the code from above into the prompt, and press `Enter`
+1. Continue playing the game
+1. When `HEY!` is logged, that means you're past the timebox!
+
+Essentially, what this code does is overrides the `showLoggedOutMessage` function so that, instead of ending the game and showing the "Please give us money" screen, it simply logs a message in the console. Just make sure to use your hacking powers for good, please 😇