I am seeking a recipe that can be made the night before and can be served at room temperature the next morning to a group of teens. Does not have to be healthy per se as these children are very active and fit. It is more a treat for them.

What about some sort of homemade breakfast granola bars with oats and fruit in them? Maybe something like one of these...

No-Bake Homemade "Cliff Bars"
Homemade Energy Bars

thanks Psychic.

Overnight oats! http://www.katheats.com/favorite-foods/overnightoats

those overnight oats look absolutely delish!