Are you looking for some opportunities in a specific area of interest? There are several math camps for very gifted students and if they are older, many Summer Institutes offered by elite universities which are worth attending because of the unique nature of the courses offered. If your kids are into the humanities, there are prestigious music camps and theater camps run by conservatories in the summer. I am not sure that all of them are still accepting applications for this year, but many still have openings.
