This is a general link resource page. On this page I try to put links to useful website. If you hover over the Resources menu link at the top of the page, you can see other resources page that deal with more specific topics.
Free Books Websites
Internet Archive – I don’t know how many old books or articles I downloaded from this website. It also has videos, images, old games other other types of media. You can also use the Wayback Machine to see how the websites looked in the past.
Gutenberg.org – a library of free eBooks.
LibriVox – free audiobooks
BOINC – The most important volunteer computing platform.
Great Internet Mersenne Prime Search (GIMPS) – the name of the project is self-explanatory. If you are lucky enough to find the next Mersenne, you will also win some money (at least $3000).
BOINC Network – BOINC related podcast and info.
https://www.distributedcomputing.info/ – website that has a nice list of distributive computing platforms and projects.
Citizen Science Projects and Online Volunteering
Zooniverse – probably the largest citizen science platform.
https://libguides.bentley.edu/microvolunteer – has many useful links to various online projects.
https://www.thenonprofits.com/ – has links to many click-to-donate websites. The money is generated from ads or maybe from deals with specific sponsors. These are small contributions, but it doesn’t cost you anything.
https://freerice.com/ – you donate by playing a quiz game and giving the correct answers. There are many categories of quizzes (language learning, humanities, math, science etc).
http://stellarium.org/ – Stellarium is my favorite 3d planetarium app.
https://www.fourmilab.ch/solar/ – interactive orrery. If you go to the home page you can find other interesting pages on various topics.