The Nowruz app contains countdown timers, as well as added information on major Persian holidays.
The application contains the following celebrations which you can toggle between:
Nowruz - The Persian New Year on the Spring Equinox
Sizdeh Bedar - Marks the end of the Persian New Year Festivities
Cyrus the Great Day - A day to commemorate the founder of the Persian Empire
Yalda Night (Shabe Yalda) - Celebrating the shortest day of the year
Chaharshanbeh Soori - The fires festival that starts the Nowruz celebrations