Championships

Championships are mega week-long events on which allow players to get ultra-rare weapons, along with medals and other tournament rewards. You earn medals from events or from boss kills (single-player or multiplayer, depending on the Championship).

Pre-release
Championships are evidently what "Super Events" were intended to be. Prior to the June 30th, 2015 update (which is when Championships were added), information relating to "Super Events" could be found throughout the SAS 4 SWF file. Four Super Event names (and their respective icons) could be found: Storm of Bullets, Elite Squads, Lone Wolf, and Zombie Blitz (with Elite Squads and Lone Wolf notably being Championships later added).

Ninja Kiwi's April 1st, 2015 update made it so players got a screen that said "Super Events Unlocked!" with an info box with the word(s) "TODO" when accessing Multiplayer for the first time after the update. This was either accidentally included by the developers, or just an April Fool's Day joke.

Elite Squads
Rewards player for multiplayer boss kills and Apocalypse Events.

The top three players were Rohan Sharpe Anforth, FsX vanilla and Jimmy70000.

Elite Squads gave the top 3 players a RIA Trident.

Lone Wolf
Rewards player for Single player boss kills, Last Man Standing and Virus Sample events.

Lone Wolf was hijacked near the end by hackers, but shortly before this the top three players were (in order) Hangel102, Jayki, and keuma. Ninja Kiwi eventually fixed the screen announcing the winners.

Lone Wolf rewarded the top 3 players with the HIKS M1000.

Trivia

 * The first Championship was a Pay-to-Win competition due to the fact that Nightmare gave you a lot of medals and you could spend NK coins to buy more tickets after your supply is depleted. The second Championship solves that problem by making it impossible to buy Nightmare Tickets during said Championship. In a later update, the solution was changed to instead make Nightmare mode not give medals.