Here is a good link that is a Tk reference -->
http://www.tcl.tk/man/tcl8.4/TkCmd/contents.htm. Then taking into
considering how Ruby/Tk prefixes the widget names with a Tk and how
Ruby treats the various parameters in hash-like fashion you should get
an idea on how to manipulate things. For example:

myLabel=TkLabel.new(myTkRoot) {text 'myText'
  font 'myFontNameAndSize'
  }.grid(:column=>1, :row=>0)