I love Moocs! Moocs are Massive Open Online Courses and you can find them at Futurelearn and Coursera. They are free courses offered by top universities all over the world. There's no written work just discussion forums to allow participants to engage with each other on line.
I've done several including
You and your money - offered by the Open University
Strategies for successful aging offered by Trinity College Dublin
Exploring anatomy offered by the University of Leeds
Researching your family tree, offered by the University of Strathclyde
Maths puzzles offered by the Weizman Institute
and quite a lot more.
Not all are on offer at the same time so you need to check regularly.
Today I have started a course about the weather. It's being offered by the University of Exeter and I'm not sure if it's offered internationally although most Futurelearn courses are but the examples in this one seem to be all British. It promises to teach about the weather with regard to walkers, photographers and gardeners so it should prove interesting and IT'S FREE!!!