Oops, it doesn't look like 'water balloon ice cream sandwich day' is a national day..

Other days

special education

Special Education Day
bounce

Bounce Day
singles

Singles Day
healing

Healing Day
eat what you want

Eat What You Want Day
lost sock memorial

Lost Sock Memorial Day
self appreciation

Self Appreciation Day
slime

Slime Day
self care

Self Care Day
azonto is acceptable

Azonto Is Acceptable Day