In Germany we celebrate Pentecost with a long weekend and take Monday off. Everybody enjoys this, although the weather sucks this year. Also most people have no idea what this holiday is about, which happens often in Germany, as we have many religious holidays that are not as self-explanatory as christmas.
So let me enlighten you with this quote from Wikipedia:
The Christian holiday of Pentecost is a moveable feast, which is celebrated on the 50th day (the seventh Sunday) from Easter Sunday. It commemorates the descent of the Holy Spirit upon the Apostles and other followers of Jesus Christ while they were in Jerusalem celebrating the Feast of Weeks, as described in the Acts of the Apostles (Acts 2:1–31).
So, please keep that in mind while you enjoy this Sunday. But first, read these five articles.