Sleep.

Last night, I went to bed at 11:30.

The significance: 11:30 is before 12:00, and I can't think of a time when I went to bed before 12:00 in the last year-and-a-half. And I didn't go to bed to read or do homework or anything else either. I went to bed to sleep. It was strange.

I was too excited about it to sleep. I'll have to try it again sometime.