To see more, hit the "#=+" button and you'll be able to use symbols like the percent sign, the hashtag, and even currency symbols for the Euro, Pound, or Japanese Yen. Unfortunately, the pi symbol ...

While the U.S. may have 11 official federal holidays, there are actually thousands of quirky, themed days that make the calendar a whole lot more fun! One of the best—and most delicious—is Pi Day.