DIR C: D:
View directory of drive C and D at the same time.
DIR /S /B
Get a list of files in the current and sub directories with their full path name (directory name + file name).
DIR /X
View the short (8.3 DOS file name) and the long name of files in the current directory.
DIR /A
Display all the files in the current directory including hidden and system files.
DIR /OS
Sort files by size -- smallest first.
DIR /?
Find out even more cooler styles (well, okay, parameters) you can use with the DIR command.