Applications are now available for PROMYS, a six-week (June 28-August 8) residential summer program at Boston University for strongly motivated high-school students (15 years or older) to explore in-depth the creative world of mathematics.  About 100 students are selected from a nationwide/worldwide pool based on solutions to challenging problem sets, school transcripts, teacher recommendations, and short essays explaining their interest in the program.  Financial aid is available as necessary to ensure all who are selected may attend.  Applications are due April 1.