GCI is a “small sibling” of Google Summer of Code for highschool students (13 to 18 years) and with much smaller tasks in several categories (like documentation, code, translation, UI, etc). The average amount of time to be spent for a task should be about three days. See the GNOME wiki for more info.
If you have an idea about a possible task, want to guide a student to fulfil it and perhaps also want to get new contributors for your project/area, please read how to write a good task and then go ahead and propose your tasks as GNOME will apply for taking part in this contest.
See you around!