Hi, my family and 20 others in our group are sailing on the Adventure in June as well. After researching, here is the information I found regarding a White Out night. It seems there is a "Glow Party, where you wear all white. The party is held in Studio B sometime around 11:30 pm on the 5th day of the cruise. They will sell glow items to wear at the party. Hint, bring your own glow items . . . ;)
Enjoy your cruise!