Pop the Popcorn: If using air-popped, pop about 1/2 cup of kernels. If using microwave popcorn, follow package directions, being careful not to burn it.

Remove Unpopped Kernels: Discard any unpopped kernels and transfer the popped popcorn to a large bowl.

Combine Ingredients: In a large saucepan, combine the sugar, corn syrup, butter, salt, and water.

Cook the Syrup: Cook over medium heat, stirring constantly, until the sugar is dissolved.

Boil and Test: Bring the mixture to a boil and continue cooking, without stirring, until a candy thermometer reaches 235-240°F (soft-ball stage). If you don't have a candy thermometer, you can test it by dropping a small amount of the syrup into a bowl of cold water. It should form a soft, pliable ball.

Remove from Heat: Once the syrup reaches the correct temperature, remove the saucepan from the heat and stir in the vanilla extract.

Pour the Syrup: Immediately pour the hot syrup over the popcorn, using a wooden spoon or spatula to gently toss and coat the popcorn evenly. Work quickly, as the syrup will start to harden.

Add the Sprinkles: Add the red and green sprinkles (and any other desired toppings) and continue to toss until everything is well combined.

Shape the Popcorn Balls: Allow the mixture to cool slightly for a minute or two so you can handle it. Lightly grease your hands or wear heat-resistant gloves. Scoop up about 1/2 cup of the popcorn mixture and gently press and shape it into a ball.

Place on Baking Sheet: Place the shaped popcorn balls on the prepared baking sheet.

Cool and Set: Let the popcorn balls cool completely until they are firm and set. This usually takes about 30-60 minutes.