I haven't seen too many of these around, so I thought I'd make one. It's simple--all you do is come up with names for each family member according to the letters of the alphabet.
DH: AB
DW: CD
DD: EF
DD: GH
DS/DD: IJ / KL
DS: MN
DD: OP
DS: QR
DS/DS: ST / UV
DD: WX
DD: YZ
Good Luck!