My first Game of D&D was as a DM not as a player, I remember it so well.
You couldn't even call it an adventure, merely a string of underground encounters - the party (that consisted of two next door neighbours and a very confused cousin) were a Thief, a Cleric, and a Fighter.
The VERY first encounter, was an Orc locked in a cupboard (so sue me, I was a kid at the time) - and I can remember the stressed look on my cousins face as his Fighter took his very first swing . . . .
Grand Memories all!