The best usage of time during quarantine is developing your coding skills in 30 Leetcode Challenge - I love it, just select your favorite programming language and solve tasks. It is super helpful if you are software engineer or just love programming. 

Decided to rededign this website a little bit. If there will be any problems with it lately, please let me know. Generally there are may things I want to do - add support of social networks, messengers, fix the registration flow which is broken for many years... Surely all this will be never done, but...