Oh, we did do t-shirts a couple of years ago and that was a success! We could do that again, especially if I can get different paints.
The puzzle wreath idea sounds really cool too.
Cupcakes could work - you get the additional eating time too, which is always a bonus
Friendship bracelets is something I'll definitely try just me and little miss, I think they might be too complicated for a group activity though. Beading could be fun though.
Great ideas, guys, thanks! Any more?