Ask HN: What term/concept should I learn next? (creating software, need help)

Every day I have about 2 hours of free time to learn something new. Problem is, when I start searching for something new, I immediately lose myself in a big number of topics I'm interested in.

After 2 hours, I read about 10 topics and after 2 days I can't remember most of it.

I would like to create my own software with a list of groups and a list of concepts/topics in those groups where I would randomly get a topic/concept and a list of links to read.

For example:

Algorithms

- sequence search

- graph search

Compiler theory

- top-down parsing

- distributed processing

So, once a day I would open my software, choose a list of groups and get a random topic.

I need HN to start with a list of groups and topics that are interesting so I can publish this application and maybe we can all learn new things.

Also, there could be a topic linked to the randomly chosen topic which will say "If you don't understand merge sort, try with bubble sort." with a link to bubble sort.

What do you think?