I got it now, it is Pentecost. Or at least what Pentecost has become now that there is no Temple for the harvest offerings and no room to celebrate a week long harvest festival camping outside :-)
Here in the US it is definitely celebrated with flowers -- beautify your home and your synagogue.
Enjoy your holiday!
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Moses got it as is. I am not a big expert in this field though. I don't think this is the US thing. There is more of a celebration in Jerusalem, I think, rather, than in other places, where it is another holiday.
It is a celebration of the day, God gave the Torah to the nation of Israel.