I'm wanting to make an ARG but I don't have any ideas. A lot of the ARGs are about “Failed Experiments” and “Monsters out for revenge” or maybe I'm just thinking about Mascot Horror Games. Point was, I don't want to do anything generic. I want something n i c e that keeps the player interested. (For those who don't know, an ARG is a game that uses secrets and puzzles to tell cryptic stories.)

I'm not sure if this is what you're looking for, but how ‘bout:
You are out exploring the deserted Temple of the Gods, a place regularly talked about by the people in your village. Of course, you’d never go in, for stories of cryptic puzzles and traps abound. It was rumored that the last person to go in there never came out (a year and a half ago), so you wouldn't want to take any chances. It took most of the day to get to the Temple through the thick foliage that surrounded it, so it was getting dark by the time you got there. Luckily, you had the sense to bring a flashlight.
Suddenly, you stumble on a rock, dropping your flashlight as you land on the ground. It rolls around a corner, and without it, the darkness is suffocating. You scramble after it, bumping into a stuck-out panel in the wall as you dive down, catching the light. You stand up and turn around just in time to see a wall sliding down, blocking the corridor you had chased the flashlight into. Now, you'll have to find another way out. Hopefully quickly…