I stopped by Home Depot today. I rarely shop there so don't know what they normally stock. I noticed a palette of 1/2" Baltic Birch plywood marked for $18.95 a sheet. The sign said "New size 5' x 5'". Yep, it was just plain weird looking. It was perfect for how much I needed but one problem - it wouldn't fit in my Van in any direction. So I bought a 4x8 and had them cut it at the 5' mark.
Bob