Ah, fun with campfires...
I could always amaze with the flaming Coffee Mate trick. A whole bottleful poured into a campfire from a meter above makes for a good display and scientific instruction. Caution kids, many an eyebrow has been lost to this experiment.
It also reminds me of other campfire games. Like betting on how a can of un-opened peaches (beans, pumpkin pie filling, peas, etc...) will explode (seam, top, other). Or that ever-so-dangerous game of "coal-toss".