1 Halfling (or Gnome, bloody light Human, Elf or 1/2 elf)
6 to 12 iron spikes for the afore mentioned character, plus 1 or 2 for the quivers of arrows
a few short (by comparison) lengths of rope
1 bow and 1 or 2 quivers of arrows
1 hammer (unless you really want to try and hammer them into the stone ceiling by hand), mace, hammer, or other top heavy implement would suffice.
Hammer spikes into ceiling
Secure character to spikes with rope, do the same for the quivers
Have everyone else looking docile below the character on the ceiling, playing the afore mentioned Nim with spare spikes if you wish.
Wait for unsuspecting bad guys to see you and move towards you - hope they fail their spot checks. Go to Comment
One morning, the sun does not rise. It seems that a great darkness has settled across the kingdom - at first, it is merely an inconvenience, but as time passes and plants begin to sicken and die, some action must be taken. As the deluded King plans the sacrifice of fifty tender virgins in the name of the Sun God, rumours spread of an ancient barrow uncovered in the hills...