Attention all Slurpee lovers! 7-Eleven is bringing back 'Bring Your Own Cup' day May 19 and 20. For only $1.50, you can fill any object with the frozen drink. 

The "cup" you're using must fit in the 10-inch slot you'd normally stick your cup in to fill, and must be watertight and foodsafe. Limit to one cup per person.