Heat oven to 350 degrees. Grease a 9 x 13 inch glass pan.
In a medium sized mixing bowl mix together the graham cracker crumbs and melted butter, press into the bottom of the pan.
Then pour the sweetened condensed milk over the graham cracker crust.
Break up the graham crackers and Hershey bars into pieces and spread all over the top of the sweetened condensed milk.
Bake for 20 minutes. Then remove from oven and carefully put marshmallows all over the top and return to the oven for another 10 - 15 minutes. (marshmallows should start to turn brown)
Remove from oven and quickly spread the M & M's over the top of dessert. Return to oven for about 3-5 more minutes.
Let cool for about 30 minutes. Then melt the chocolate chips in a microwave safe bowl or container. Drizzle melted chocolate chips over entire dessert. (Or you can put melted chocolate in a baggy and clip the corner and pipe over all of the dessert).
Let cool for about an hour. Then slice and serve!
Notes
You could also make the crust out of:
Sugar Cookie Cookie Dough
Peanut Butter Cookie Dough
Vanilla Wafer or Teddy Grahams (crushed with butter)