When my Sunday School class studied the Day of Pentecost, we counted 50 days from Passover to today, June 4th. (also the birthday of one of my students, which made it easy for us to remember when it was coming) Some places say that Pentecost is next Sunday, June 8th, but we were right according to the Jewish calendar. http://www.jewfaq.org/holidayc.htm
The Pentecost after the resurrection of Jesus was a miraculous day - when the Almighty God chose to put His Spirit in us, his creation! The more I think about this, the more I want to let Him work through me, for "all things are possible with Him."