From their website:

Free Ice Cream Day

Join us Saturday May 30 at your local Walmart.
11 AM to 4 PM.
One sample per customer.

Available items:
• 1.57 fl oz. Dibs Snack Bag
• 2.4 fl oz. Blue Bunny Aspen Frozen Yogurt Granola Bar
• 4 oz. Ben & Jerry's Flipped Out Cup.

List of participating Walmart locations