There are several countries who extend their national day holidays by one day. There are also countries who have a national day of service (In the US, MLK Day and September 11th are days of service), but these are usually not public holidays. 

In Dominica, they uniquely combine these two traditions, with the day after Independence Day being the National Day of Community Service.  

The Day of Community Service began as an initiative to clean up the mess left after the independence Day celebrations but has now become a day when all citizens turn out to complete approved community projects in a single day. 

Dominica is one of only two countries whose flag features the colour purple. The other is Nicaragua.