You mean happy 1/2 Tau day! On Tau day you get to eat the whole pie, on Pi day only half (because Pi radians is only 1/2 the way around the pie, but Tau (being 2*Pi) is all the way around!)

Read somewhere that Tesla was going to increase the prices π% instead of 3% in honor of π day since they're so close, I guess they realized that would be irrational.