This random game came to mind, so I just thought I'd post it.
Basically you say a type of family member. Like mom, dad, aunt, uncle, grandma, grandpa, etc.
The poster below then is related to you in that way.
Example:
DOODLEboy99: Dad.
DOODLEgirl99: Sister
That would make DOODLEgirl99 my dad(Ew. o_o)
Then the process repeats.
I'll start things off.
Er...cousin.
GOGOGO
Gay stalker cousin.