It was pretty clear to us that the problem was ours, and that we didn't want to turn it into Mom's. Otherwise, she was liable to cure our boredom with an exciting round of chores, and no one wanted that.
Her other favorite thing to say was: 'Use your imagination.' This occasioned much eye-rolling and complaining, at least until it became clear that she wasn't interested in our whining. Then we'd imagine, loudly, what it would be like to have a mom who wasn't so mean, while she stifled hysterical laughter in the next room.
Occasionally, my sister would be bored and I'd be otherwise occupied. Then she'd explain to Mom that she couldn't use her imagination, because she didn't have one. 'Jen has all the imagination, and she won't play,' she'd complain, as if I were hoarding marbles or crayons and wouldn't share.