Originally Posted by MSPeconomist

There's likely to be some sort of skating, ice or fake, in a city square.

Look for outdoor carolers and indoor holiday music performances, often held in historic churches. Many churches will have beautiful antique manger scenes as well as holiday decorations. Hotels, restaurants, and generally shops, windows, and downtown streets will be decorated.

Remember that the 26th is the second day of Christmas and considered a holiday, so check what's open.

Something that's unique to Vienna would be the performances or practice sessions of the royal dancing horses.