For whatever reason, when I first started getting into Dungeons and Dragons it was the AD&D Books that caught my eye. I remember using my allowance to pick up all of the old yellow spined 1st Edition AD&D books. My first experience with the original Red Box (which came out at the same time as 1st Ed AD&D according to Wikipedia) was when my next door neighbor inherited it. I remember that it was used because whoever had had it before had created a whole bunch of index cards for each of the rooms of their dungeons all in pencil.