None of my parents have taken tests, but I'll try to rationalize it.
Mother dear: INTJ
Reason: I can clearly see Ni and Fi in her, and that quite strong, and she is a very capable organizer (Te). Usually critical and skeptical, but founded with Fi in regards to family.
Father dear: ISTP (?)
Reason: Much more uncertain of him. He is however an excellent entertainer (parodies and the like), loves to do loner-things which give sensory stimulation (go hiking, fishing, listening to music, such things) and hates far out ideas. Unorganized P-like. I see Fe developing in him, albeit this was not a strong point in him before. Are usually capable of dealing with aggitating people (you know, those threatening and angry people), but are more frustrated with people who close up and turn inward in distress, like me (T quality?)
Roomie: consistently tests as ENFJ but i just don't see it...she is rather immature, so maybe that's it (great friend of mine and great roommate but is a bit of a prima donna)
Best friend: ENTJ
I'm 100% positive on all of these. Being the NFP that i am, i immediately typed everyone upon discovery of MBTI :P
"How dreadful!" cried Lord Henry. "I can stand brute force, but brute reason is quite unbearable. There is something unfair about its use. It is hitting below the intellect." ~ Oscar Wilde - The picture of Dorian Gray
Father = ENFJ (great father, changes his mind often though),
Mother = ISTJ (lol no one likes her, the very definition of a duty-filling inspector if there ever was one)
Sister #1 - INTP (hey i'm a tomboy!)
Sister #2 - ISFJ (must conform, everyone must like me)