Dueling. I say we use it as an option to reply to a civil lawsuit. Able bodied adults only, no proxies, and if you refuse then you have to do a trial and they can weigh your refusal as evidence against you.
The last formal duel in the western hemisphere, occured in 1968. Pretty sure some lemming were already alive at this time, and most of us had parents alive at this time. It was between two french politicians after a heated argument at the parliament.
Benefit is that dueling was primarily done by rich white guys over issues of ego, so our tech CEOs would fit in just nicely whilst having the join benefit of removing half of them from the gene pool