It's as simple as it sounds. If you can't conceive of a personal Hell, then describe a unique version of Hell altogether. Here's mine:

I'm strapped into a cold metal chair in a medium-sized rectangular room, my body and limbs are rendered immobile. On my lap in front of me would be a MicroKorg barely out of reach from my restrained hands. I do have a controller within reach, but it's connected to an Apple IIe with a phosphorus screen fruitlessly emulating an electronic version of the game, Mastermind. The room reeks of Taco Bell, but I never see any food. Speakers in the back of the chair continuously emit the vocal sounds of a female having the most extreme build-up to orgasm ever, and it just cycles and recycles, over and over. There's a Keno board, but the numbers I yell to the attendant are never picked. What an awful place!