Um, in my 1st year on team (2nd year of team)... the ThursdayFriday/weekend before shipping went something like this:
skip 6,7,8th period for robotics
work after school till 6
go home, get food
work at Doug's basement or Cornell till 4am
on sat: go to norwich, get back at 2pm, work till 3am, home, etc.
We did nicely last year and many people put in hours similar to this - not sure about the skipping classes part though
This year, Steve and I often worked 2-3 hours extra at either my house or his to finish up drawings/designs/inventory. But hey, I did it this year and last because I know I won't have time for it this year (junior).