I was there all afternoon, but spent most of it catching up with various people. So I didn't get to see as much as I'd have liked. Rob and Darren were there as well, and may have more info.
However, I did spend a little time assisting with the Nottinghack soldering workshop, and by the end of the day they'd taken over £200 for their flashing badges. Most of the customers were kids, so a similar simple "learn to solder" project would be viable for our group. (There are plenty of local events we could do this at.)
Have already emailed a few people with some other project suggestions, but I'll post them here as well for completeness:
Static / mains detector (very easy and cheap)
Festive flashing lights (card or novelty project)
"Squeaky box"
Persistence of vision wand (Arduino based)
Shock box
Mousebot
PIR night light
Musical tube ("wave around to make a sound!"TM - possibly Arduino based)
Shaker torch
Plant watcher (light, temperature, humidity, moisture)
Obviously all electronics based at the moment due to current lack of machinery, but most of these are cheap (£1-5 range). Some may require a bit of assembly, but we can probably work out some way of simplifying them and selling them as kits.
A simple way of adding value would be to include an explanation of why they work. That way they become educational as well as fun.
andy