Sounds like you are going to one of those pampered SoCal highschools.
I don't have block scheduling, there are 8 class slots a year. Four first semester and four second semester. I simply took a free period instead of a fourth period both semesters, so I'm only taking 6 classes this year (3 a semester). It is, however, an open campus for people taking free periods. I don't have to check in or anything, I just go home early.
Second semester (when I go back to school, I just finished my finals today) I'm actually taking a "zero period" which means I'll go in to school early in exchange for a free fourth period. Since I'm also taking a free third period by choice, I'm going to get out of school after second period which is lunch. Going home at 11:12 AM is gonna be awesome.
Don't get me wrong though, I'm not saying my school isn't pampered. It's in the top 15 highest scoring public schools in CA so we have a budget the size of Croatia's national bank. Not to mention the ASB department of my school received like 5 million dollars in donations this year alone..