Which activity will have the greatest effect on making an intoxicated person sober?

The most effective activity for making an intoxicated person sober is time, as the body needs time to metabolize alcohol and eliminate it from the system. While drinking water, eating food, or engaging in physical activity can help mitigate some effects of intoxication, they do not speed up the metabolism of alcohol. Ensuring the person stays safe and comfortable until they are sober is crucial. Ultimately, only time can truly sober someone up.