As close to the real thing as it gets. If it is as dry at your house as it is at ours, this may be a more practical option this year. Bonfires are just out of the question right now in our part of the country.
I had seen them all over Pinterest, but had never tried it myself. While attending my niece's wedding (country wedding posts here and here), I was "in charge" of helping at their smore table. My brother-in-law, had built the troughs and then filled them with river rock. They had 3 kinds of marshmallows, 3 kinds of chocolate, and 3 kinds of graham crackers. The smores bar was a hit!
Last Saturday we had an impromptu "Barn" party at our house and we love to finish it up with roasted marshmallows and smores.