Designers and recreational users alike will often find themselves looking to use special characters, like numerical fractions and trademark/copyright symbols.  The Glyphs Palette can save you the hassle of tweak, tweak, tweaking your standard text until a fraction looks right or creating a symbol by manually combining shapes and characters.

To open the Glyphs Palette, goto Text > Glyphs on your Illustrator menu.  The palette will open and display the glyphs available in the selected font.  Simply change the font on your Character Toolbar or Palette to change the glyphs being displayed.  To insert a glyph, place your text cursor somewhere on the artboard or with a line of text and then double click the appropriate glyph within the palette.