Instead of assigning person-to-person debt relationships, my company just tracked the sum of each person's net debt on the whiteboard, with a circular buffer lo

Instead of assigning person-to-person debt relationships, my company just tracked the sum of each person's net debt on the whiteboard, with a circular buffer log so we can go back and fix things in case the sum doesn't add up to 0. The trouble with that is when people are too lazy to update the sum, so they end up hoarding a bunch of receipts and then update it way later. Eventually some numbers got really big, so I put some offsets on the board so that infrequent participants' contribution to the sum was zero. And then people left the company with nonzero debts... Another option that we've started doing is to just randomly assign the task of paying for a meal, weighted by each person's proportion of the cost. Once somebody has a debt to a coworker, though, the most efficient way of paying it off is to bet double-or-nothing on a coin flip until the debt is zero or the debtor is uncomfortable increasing it further.