Google Summer of Code and Season of Docs programmes aim to introduce students and recent graduates to open source contributions. I participated in GSoC some years ago and it certainly encouraged me to contribute to other projects afterwards.
There are some familiar names among organizations that participated last year such as Python Software Foundation, Django, Julia or (more closely related to some of Jupyter projects) Eclipse, which had a project focused on collaborative edition features (among others).
I just wanted to bring this to your attention, and encourage to consider whether you would be interested to participate this year to promote Jupyter and attract new contributors. Each organization needs a few mentors to guide the students, which is a part-time commitment for a few months (there is a symbolic payment from GSoC to organizations for each mentor); preparation of a few project proposals is also needed. The organization application window for GSoC this (2021) year is Jan 29 - Feb 19.