I recently came across the term 自由課題 in this context:
アイスの棒で作ったおうち
自由課題はこれでクリア!!
For reference, a character just finished building a house made of popsicle sticks.
I assume it roughly means summer project but could not find anything to support this online.
I think summer project is a good working translation. The dictionary entry suggests it could be literally anything you've done of your own initiative and have achieved, but I did a google search, and there are mainly results for arts & crafts-y type things in the summer e.g. some young children doing calligraphy, some older children doing painting, this robot giraffe kit, somebody who has built some architectural models, and this museum's summer programme, amongst other things. So, it does seem to be used mostly for younger people and projects they are doing outside of the classroom, but the dictionary doesn't strictly go that far to narrow it down.
