This is what I did today. I was a helper at Techlinks at Duxford airfield. My engineering chum talked me into it a couple of years ago and I enjoyed it sufficently to volunteer to go back each year. This year, I was helping with the Jitterbug.
Hard work though, 40 children in groups of 4 to see through an hour-long task, then a few minutes later, during which time you frantically refill boxes of equipment, another 40.
Some really great children this year, sometimes you have groups who can't work together, of don't listen to/read instructions, or wait passively to be told what to do, but this time most of them independently read the worksheet, checked the list of equipment, did the right thing in the right order and were happy to go off with their completed item.
So yes, all being well, I'll be back again next year.