At work, I have a positive attitude and remind myself to be ready for anything. Yelp,, and related marks are registered trademarks of Yelp. Founded by Elsa Kopp in 1950, the restaurants continue to be heralded by local publications for their quality food. February 24th National Tartar Sauce DayKopp's Fish Sandwich. Home of the famous 'Flavor Forecast', Kopp's was the first custard stand to offer a special 'Flavor of the Day' in addition to chocolate and vanilla Often, featured flavors are related to events for that day or month.