5. How to Customize Calendar Time Ranges
If you generally don't have anything scheduled at 3 a.m. (except for sleep, hopefully), the "Hide morning and night" feature lets you customize your calendar so you see only events within the time range of your choice.
Click the gear icon in your Calendar view, then select "Labs." Find "Hide morning and night," click "Enable" next to it, then "Save."
On your main Calendar view, you'll notice a gray bar that appears in the column with the hours of the day. Adjust the time range by clicking and dragging the bar at the top to the desired start time, and move the bar at the bottom to the desired end time.