Every one has a cellphone. Almost everyone has their cellphone on them at this exact moment. This means everyone has an electric circuit on them. Your cellphone when not in use has about 50-60 volts of power flowing through it. These electrical circuits are everywhere. Your house has countless amounts of circuits in it as well. From your outlets to your hair dryers to video games we use circuits constantly. This would include series, parallel, and even a combination of the two.
It's astonishing to think how many times we use circuits of something that is operated by circuits. How many times a day do you use circuits?