Many students may not be aware that renewable biological materials can be converted into multiple bioproducts and biofuels using a biorefinery process, a more sustainable alternative to conventional crude oil refineries. By using waste from pineapple, a plant material that most students are familiar with, a biorefinery can be modeled to demonstrate the benefits of a circular bioeconomy. Pineapple waste consists of the peel, core, and leaves that are often discarded after the fruit is processed for consumption. These "leftovers" or "residues" are rich sources of sugars and lignocellulosic biomass, which can be converted to value-added bioproducts and biofuel. In this article, the development and implementation of a high school laboratory activity that simulates a pineapple biorefinery is described. It was field tested with an Environmental Science class, in which students converted pineapple leaves into paper, and they fermented the sugars from the core and peel into bioethanol for fuel. Students investigated how different process variables influenced the tensile strength of their paper and the quantity of bioethanol produced. This lab introduces students to the potential of a circular bioeconomy and challenges them to integrate prior chemistry and biology knowledge to generate solutions to real-world sustainability problems. It can be used in chemistry classes to demonstrate stoichiometry, chemical reaction yield, chemical bonds, and the effect of reactant concentration on the rate of product formation.