My wife is a stay at home mom. I sign her up for nearly every card I sign up for. Since March, we've accumulated over 750,000K points and miles, as well as elite status at 3 hotel chains and an airline. She thought I was nuts until the first time we got bumped up to first class on a dirt cheap domestic fare, and then stayed at a Presidential Suite at a Marriott for free. Now she rolls her eyes, but goes along with the program.

Nice side effect benefit is that her credit score is even higher than mine! Guess it helps to have plenty of credit that gets paid off.