What is a siesta?
Siestas are historically common throughout the Mediterranean and Southern Europe, the Middle East, mainland China, and the Indian subcontinent. The siesta is a tradition in Spain and, through Spanish influence, most of Latin America. In Dalmatia (coastal Croatia), the traditional afternoon nap is known as pižolot (from Venetian pixolotto ).
How much does Siesta cost?
The SIESTA program has been always free for academics, and is now distributed under the GPL license. Currently there are several thousand users all over the world, and the paper describing the method  has received more than 7,500 citations so far.
What makes SIESTA so efficient?
SIESTA’s efficiency stems from the use of strictly localized basis sets and from the implementation of linear-scaling algorithms which can be applied to suitable systems.
When is the best time to have a siesta?
In many countries that practice the siesta, the summer heat can be unbearable in the early afternoon, making a midday break at home welcome.