As we do not believe in Jesus' atoning sacrifice, the festival is celebrated in a typical Jewish fashion.
Shavuot is the day the Torah came down with Moses. We must eat honey and milk products on this day. To remind us of the sweetness of the Torah.
A handy guide to know more about the festival from a Jewish point of view is at, http://www.gojcc.org/wp-content/uploads/2013/07/guide_shavuot.pdf
To learn more about the holiday visit Chabad.org at http://www.chabad.org/holidays/Shavuot/default_cdo/aid/111377/jewish/Shavuot.htm