I like the look of this fabric draped on rods hung from the ceiling. If you love a canopy bed, but don't want to buy a new bed, maybe this would do the trick. I pinned it one time on Pinterest from HERE.
Here is another fun false ceiling, only it's not fabric - it's plastic table cloths from a dollar store.
This is a fun and colorful look - and it is probably a lot cheaper than fabric.
I found this on Pinterest