Hello,
You can include a tri-color dress code for all staff on Republic Day. Also, the entire office can be decorated with tri-color balloons and flags, along with a small flag on each workstation. This will create a feeling of patriotism all around.
Organize a quiz competition among your staff. Frame the questions in such a way that the answers should contain information about our constitution, as it will enhance our knowledge about it.
WISH YOU A HAPPY REPUBLIC DAY!