Play the ABC story. You start the story with a word, and say two sentences of a story, then pass it on and whatever letter was last in the word you ended on the next person has to start with, and so on.
Bring a deck of cards and ask random questions, taking turns flipping them over. If its odd its no if its even its yes.
If its warm enough outside play skunk in the barnyard. Its like hide and seek tag. One person counts, as the "farmer", and everyone else hides as "skunks", but counts to ten after the "farmer" says ready or not. After their ten count they pop up, yell "skunk in the barnyard" and run to another hiding spot. This game works really well with a lot of people, but Im sure it would work with 3, and if there are neighbourhood kids?
make painted paper plate pinwheels and suspend them from the ceiling.
Teach them how to make a garden in a pop bottle.
Stack up the sofa cushions like a staircase and see who can get the highest without toppling.
OR...if they happen to both be rowdy rambunctious 9yr old boys...you could do what we did...
tie a string around barbies foot and hang her from the ceiling fan, then turn it on and DUCK! LOL.