Summerslam is the biggest paper view in the summer. Usually, the king of the ring headlines this event and gets a world title shot. Summerslam is almost Wrestlemania quality and it is from the Big Four.
TLC is Tables, Ladders, and Chairs. All three of these match stipulations are used in the show until the TLC match happens in the main event.
Extreme Rules is paper view with special stipulations in matches with extreme rules. This paper view comes right after Wrestlemania and it is memorable for it's extreme moments.
The King of the Ring paper view is a 16 man tournament with the winner being called the king of the WWE and main eventing Summerslam for a shot at one of the world championships.