 The Independent Activities Period is a four @-@ week @-@ long " term " offering hundreds of optional classes , lectures , demonstrations , and other activities throughout the month of January between the Fall and Spring semesters . Some of the most popular recurring IAP activities are the 6 @.@ 270 , 6 @.@ 370 , and MasLab competitions , the annual " mystery hunt " , and Charm School . More than 250 students pursue externships annually at companies in the US and abroad . 
