June 21...

is summer solstice in the northern hemisphere and winter solstice in the southern hemisphere. Because of the extreme position of the Earth at this point, any sharp movements could send us all spinning away into oblivion.

is Go Skateboarding Day, a day adopted in accordance with graffitied signs that had originally read "no skateboarding". Skateboarding is a healthy past-time fully supported by the Australian Orthopedic Medical Association.