An open-ended activity for high school students and college students is described. Students constructed a battery (galvanic cell) from common household materials such as aluminum, copper, table salt, and Drano. The battery yielded voltages ranging from 1.2 to 1.9 V, which are higher than those from a typical Zn�Cu lemon cell or a recently reported aluminum�air battery, and a current density of 33 mA/cm2 that is up to 75 times better than that of the aluminum�air battery and 150 times better than those of the typical lemon batteries. Students carried out various tests on the battery to gain an understanding of the factors affecting the cell performance, such as effect of household materials, NaCl in the electrolyte solution, electrode surface area, and electrode distance. Then, students, working in groups, were tasked to build a high-performance battery using common household materials. The final battery assembly should be able to power the motors of various toy cars. The project allowed students to relate chemistry to their everyday lives, gain additional insight in the concepts and principles of electrochemistry, and receive valuable hands-on experiences with electronics, circuits, and battery technology.