(from lernu.net):
...Ok, we admit it. Not exactly a week, but eight days.
NASK, the North American Summer Courses, is a great way to jumpstart your Esperanto skills. Esperanto students young and old can rapidly improve their Esperanto skills with lots of personalized attention from NASK\'s team of well-known international teachers. Spend eight days in an environment of Esperanto immersion - classes, excursions, and free time, all in Esperanto.
NASK 2012 will be held from June 25th until July 4th at the University of Texas in Dallas; only one week remains in the early registration period. Register now, and save 50 (US) dollars!
Scholarship help is available, especially for full-time students, teachers, and residents of Latin America.