Can anyone explain how the LoL season works?

Does anyone know how the season is laid out? I could take someone who's never heard anything about football and explain to him or her in 15 min or less how the season works (ie, preseason, regular season, post season, etc). I could even go over some of the other parts of the year like the draft and training camp. It all makes sense. But when I try to understand LoL's season structure, I have no idea what I'm looking at or what the significance of this weekend's "invitational" vs next weekend's "split".

I've posted this before but never got any good responses. Just a few replies of, "well it kind of works this way" and "it kind of works that way but I'm not 100% sure". It would be nice to enjoy LoL the same way I enjoy watching football if I just knew what was going on.

My friends and I were going to try the Fantasy draft with LoL but we laughed because not a single one of us ever understood the season and how it works. So how would we even know who to pick and for which weeks?

Despite the growth in the recent years, I believe Riot Games is missing out a lot on the potential spectator market that's out there.

Can anyone help us? Thanks.