Botif (notif)
Botif is a program that displays text in a box in the middle of the screen. Text is read from stdin and the box is sized to fit it.
It supports unicode, although not proper text-shaping, mostly due to the limitations of the built-in X text rendering system.
You can specify background and foreground colour, XLFD font, border thickness, and margin/padding size.
As a fun example, use ls -al | botif -b darkcyan -f yellow
to display files in the current directory, in (dubious) style.