June 1st is my sister's birthday, and the start of about two weeks of odium in our household as my sister and I, 'Irish Twins', engaged in a mutual nastiness campaign while we were officially the same age. It was always a weird period because, when my birthday finally rolled around, our usual comity returned. Everybody pretty much knew that we'd be impossible for this period of time and everybody pretty much just dealt with it.
My sister has mellowed out considerably in the intervening years, and her kids are just about the nicest boys you'd ever want to meet. Her husband, a rocket scientist like her, just retired from the USAF, and the family will be moving back east to the D.C. metro area. With their move, I'll be seeing a lot more of them... we don't have any awkward two weeks of mutual antagonism anymore.