Simple. The world for your D&D game - or whatever other RPG you are playing - should have cultural holidays of its own. These holidays also serve you as a GM. How? They give you a way to show what is important to the country or kingdom, and with that give a bit of history to the world.
So what does your setting celebrate? I've provided some examples below:
- The birth of a ruler
- The birth of an heir
- The anniversary of a famouse battle or major military victory
- Celebration of independence from another nation
- Celebration of the formation of a kingdom or empire
- The beginning of planting season
- The end of planting season (aka harvest)
- Religion based holidays
- Other major events
You don't need to have all of these, but holidays - and the festivals that often go with them - give a sense of life to the setting, a sense of history, and a sense of value. Give some a try. Sprinkle them in your game. Let the players enjoy them. It might do a lot of good.
With that, a Happy Canada Day to those in Canada, and Happy Independence Day to those in the States. If there is a post on Monday it will probably be something light. Have a great weekend folks!