What about sleepover parties?

I was on tv last week and wrote about it here.

 

Can we talk sleepover parties?

They kind of baffle me, and I've realized it's because all I know are slumber parties with girls, so I really don't know what happens with boys at sleepovers.

How old were your kids when they started being invited to them or going to them or having them?

How many kids usually go?

Are there ages at which they're co-ed, or are they always single sex?

In NYC the first one we got an invitation to was in second grade, and there were around 8 boys. My older son went to one last weekend here in Michigan with what seemed like a thousand boys. My first-grader suggested having one, but we thought it might be too soon and talked him down to a daytime party.

Do girls still do the same social bullying games we did in middle school to the first person to fall asleep?

Do boys do that same stuff, or is it more straightforward?