I don't know what site you're referring to but take a look at CoderByte and Project Euler
khanacademy.org
code.org
codecademy.org
None of these are what I'm looking for. These do have programming exercises. However, I'm looking for a very specific type of exercise: a problem is given, and an incomplete solution is also given, and the student is asked to fill in the blanks of the program to make it work.
try codecombat.com // not sure its what you are looking for but similar enough..