Grilled fresh fruit over vanilla ice cream is an ideal dessert for summer nights.
In a medium bowl, toss together nectarines with sugar; set aside to macerate, about 15 minutes.
Heat grill to medium. Stack two pieces of 10-by-12-inch heavy-duty aluminum foil; place on grill. With a slotted spoon, transfer nectarines to foil; reserve any juice that has accumulated in bowl. Cover grill, and cook until nectarines are charred and softened, turning occasionally, 10 to 15 minutes.
Return nectarines to bowl; add blueberries, and toss to combine. Divide fruit evenly among four serving bowls; drizzle reserved juice over the top. Serve with a scoop of vanilla ice cream, if desired.