This year's SANS holiday hack was pretty fun, and quite varied: https://www.holidayhackchallenge.com/2018/ https://www.holidayhackchallenge.com/2018/ Also, htt

This year's SANS holiday hack was pretty fun, and quite varied: https://www.holidayhackchallenge.com/2018/ https://www.holidayhackchallenge.com/2018/ Also, http://overthewire.org/ http://overthewire.org/ is fun, and https://www.wechall.net/ https://www.wechall.net/ has a list of several CTFs.