Stopping time!

[GrinningManiac]

I'm ashamed to say that, despite all the obvious Setting Up Elaborate Pranks and doing other things, I would likely perv on people

The temptation would just become too great

 

[lacktheknack]

I would just freeze time to get more sleep.

THIS.

Otherwise, I would use it to fight crime in the criminal underbelly of the world's famous cities.

(This all assumes that I don't age during a time-stop).