Today is perhaps the least celebrated of German holidays...but people do have the day off. It's the Tag der Deutschen Einheit, or Day of German Unity, commemorating the Fall of the Berlin Wall and Reunification. 21 years since Germany was divided.
Interestingly, the most dramatic, emotional day was 9. November 1989, when the wall was opened...but this day has a long and complicated history in German history...the anniversary of Hitler's attempted coup in 1923, and then the date chosen for pogroms against Jews (Kristallnacht) in 1938. So they chose the "official" date of reunification, Oct. 3, for the holiday.
In the US, most of our holidays have national symbolic value (Fourth of July, Thanksgiving, President's Day, Memorial Day, Columbus Day, Martin Luther King, Jr. Day, etc.), and in Germany most national holidays (where everyone has the day off, all stores are closed) are religious holidays. This also means that it depends on which state you live in, a Catholic or Protestant state. Bavaria has the most holidays, and Berlin actually has the fewest. So their schoolkids also have fewer days off than in Bavaria.
In the U.S., there is hardly ever a day when you can't go grocery shopping (at least for part of the day!), or go shopping shopping, but in Germany things really shut down for holidays (and mostly on Sundays, too). People go for walks, enjoy their day off and their time with the family. The pace and noise-level of the city changes dramatically. No last-minute Christmas shopping or Sunday trips to the grocery store to stock up for the week.