Art of Problem Solving (AoPS) web community and school provides real-time instruction through a virtual classroom where students and teachers communicate via live text-chatting

A life changing, two-week summer program for 8- to 11-year-olds who are profoundly gifted at math. Building strong friendships is as important to personal growth as academic achievement.
The Gifted Child Society encourages the overall well-being of gifted children, through each stage of their development, and provides inspiration and unique enrichment programming and services to gifted children in pre-K through 8th grade. 
self-paced, computer-based instruction through brief, pre-recorded multimedia lectures.   Students can also sign up for tutorial guidance from an instructor by phone, email, or the web