A Word on Competitions
The competitions list is not exhaustive, because resources such as CTFtime.org already exist to provide more comprehensive lists of competitions and their dates. Note which competitions are hosted online, which are exclusive to conferences, and any other special cases (i.e. must be a student) which may be required for participation.
A Word on "Just for Fun"
If you are serious about learning to code and hack, the "Just for Fun" page is probably not for you. That's not to say you won't learn anything, but these games are better suited for you if you are just looking to kill some time, learn casually, or take a break by playing a coding/hacking-themed game.