As Shakespeare would say (if The Bard was writing for Apartment Therapy): What's in a name? A ceiling medallion mounted on any other surface would look as beautiful. So try not to get so hung up on the "ceiling" part of the label. There are a few other ways to use these intricate architectural features to dress up your vertical surfaces. Just check out these DIY projects.
It's a little early for the holidays, but bookmark this idea to try out a medallion as a modern wreath, seen here in Christmas and Halloween editions from This Old House and Better Homes & Gardens, respectively.
A ceiling medallion can be modified into a mirror, like here with a tutorial from DecoArt.
And finally, you can use a medallion as the base for a DIY side table or nightstand, just follow these instructions from This Old House.