A friend of my wife died last week. Friday night we headed out after work on the 10 hour drive to get back to New Mexico in time for the 10 AM funeral service.
Given how tired I was, I tried some Five Hour Energy. It definitely helped me stay awake. However, when I tried a second one (it was a long trip), I found that you can't get ANOTHER five hours out of another shot. (Hardly surprising.)
Downside. It tastes AWFUL! I tried berry and lemon lime. They were both absolutely awful. However, the lemon-lime tastes so bad it definitely gives you a head start on staying awake.