My parents had to put up with a lot on car trips. My sister and I found ways to entertain ourselves that ranged from silly to educational to combative. They were all loud. The educational games were the ones that eventually broke my parents.
As the elder child--two years older than me--she knew everything (still does).
She liked to test me on my schoolwork, but she would get frustrated by my slow responses. If she asked, "what's ten plus six