I brought a book with me so I could read. Reading inspired me and so did having to go to a psych hospital in the first place, so I spent an inordinate amount of my free time writing. I filled every single page of a composition notebook, and I was so lucky they let me have a shitty half-broken pen. Whenever I got to talk on the phone, I called my mom and read it to her.
I know some people drew or colored, if we got the opportunity since there was literally a single box of art supplies and we had to share it with the entire hospital. Since they let us have crappy pens, some people doodled with them and colored it in when we had supplies again.
I also sang. I asked one of the nurses, the coolest one of course, to print out the lyrics to a couple of songs I liked so I could sing in the quiet room at like 5AM. My argument: its my 'best' coping mechanism. That angle worked, but I was lucky that they sent me somewhere with a good collection of people and staff, as I went through the ER.
But most of what I did was attempt to meet every singe possible criteria so I could get out before they charged me an arm and a leg for what amounts to absolutely zero support.