Use the mobile phone app Vine to record looping 6 second films that can be linked to the Unit webpage. The app is simple to use with no editing needed. the only available effect is stop and start, so stop motion is very easy.
Give the Explorers a simple brief as it will only be a 6 second film when finished. Perhaps see if they can show how to tie a knot in 6 seconds, or better still put away a pop up tent.
As many Smartphones or tablets that can download the free Vine app as belong to your Explorers. There is no need for internet access while the film is being made as the phone will download the film when access is available. It helps if you have a projector or large screen connected to the internet so that you can show the finished products on the night and you can run a competition to see which gets the most likes.
If you have a Unit twitter or Vine account then the individual films can all be linked and "revined"
Show the explorers some of the better stop motions or films on vine to start the evening, perhaps record and upload one as they watch, then give them as much time as you want with a brief to produce a 6 second masterpiece on a scouting or green of any other subject.