Display Sentence in Alphabetical Order
GolfScript, 24 / 6 characters
{26,{65+.32+}%?)},{31&amp;}$

Example:
&gt; Johnny walked the dog to the park.
aaddeeeghhhJkklnnoooprtttwy  

If the input is restricted to printable ascii the code can be shortened by three characters using {95&amp;.64&gt;\91&lt;&amp;}, as filter.
Can be tested here.
The can-be-ignored version is even shorter (6 chars):
{31&amp;}$

and yields output
&gt; Johnny walked the dog to the park.
      aaddeeeghhhJkkl.nnoooprtttwy