Thursday morning

Well, today I was woken up rather rudely by my husband. Turns out, the alarm had gone off, but our 2 year old had so thoughtfully turned the volume all the way down. So, I had to get up and make somehting for Jeff to eat on the road so he could get out of the house not to late. Then I just decided to stay up because I have to get up to get the kids out at 6:30 anyway and by the time Jeff left it was 6:00, not much point in trying to get more sleep. My kids HATE getting up and having to get dressed and ready for school when it's still dark out. Of course, in the summer, they don't seem to have a problem getting up at 5:00 am. I want to know why they sleep in until 7:30 on every day but Saturday. Anyone have an answer for me?