xtextbg renders text with Xft and sets it as root background. so you can set fortunes or other stuff you like your background.
xtextbg is aware of \n. xtextbg is not aware of any other control characters. xtextbg will assume stdin is valid UTF-8.
you need Xft and Xlib development libraries. libxft-dev and libx11-dev are the Debian packages.
if you are using something not Debian-ish, modify the Makefile so that it points to the X11 and Fontconfig libraries you use. you can also change the prefix to point to whatever unusual path you use.
modify config.h so xtextbg uses the font and color you want. then make clean install.
xtextbg x y. it will read() from stdin which means you can enter only one line via the console.
echo "fancy quote" | xtextbg 100 100
or
cat > multiline_fancy_quote << EOF
...
xtextbg 100 100 < multiline_fancy_quote