Both, participating when needed and supervising the rest of the time. I may be kicked off the team though as I think my father may be getting sick of my supervising.
Me. "It's a bit crooked don't you think"
"those things are a bit out"
"shouldn't you be doing it this way"
"are you sure thats right"
"no that's deffinately wrong"
"that bit there is a bit wobbly"
And my favourite "are you sure it's big enough?"
"i think it is a bit small"
"maybe we should be making it bigger"
"now that I look at it properly it is deffinately too small"
"is it really too late to make it bigger"
"oh well, I guess we can always make another" I love the look of horror on his face when I say that.