In a small bowl, add the vinegar, sugar, salt and pepper and mix until the sugar and salt dissolve. Add the blueberries and let sit for an hour or so.

Heat the barbecue on high until it's good and hot. Carefully place the oysters on the grill side, with the flat lid of the shells facing up. Do not turn or move; wait patiently until you see the first signs of the oyster opening. Some will pop right open and some will not, so as soon as you see a small crack, take it off the heat and pry it open using a small paring knife or an oyster shucker.

Spoon liberal amounts of vinaigrette over the top and eat immediately.