How to keep the elderly occupied

Let me start by saying,  I love my mother aka mum.
My mum is 76 years old, doesn't walk and she's as mean as the day she was born, but she's mine (and my brothers) only mum.

Mum is often bored.
She claims to have read every book on earth, even those that have yet to be written.
She's heard every song on earth, they all sound like "a buncha no talents warbling".
She's seen every movie ever made, even those never made, and they're all evil.

Needless to say, finding activities for my mean as hell, mum, is quite the challenge.
Until recently, I had abandoned all hope in keeping mum happy, in the least sense of the word. Then it happened! The phone rang! A number I didn't know. Normally I would send it on to voicemail but not this time ... this time I hit the button to answer and told mum "it's for you." On the other end, a telemarketer trying to sell a "free home alarm system". Mum kept the poor person on the phone for over 30 minutes, telling her life story, asking questions about the security system she was never going to buy, telling more of her life story ... until she finally informed the telemarketer that she wasn't going to buy.
I got 30 blissful minutes of no complaining, no swearing, no rude behavior.
Do I feel guilty for unleashing my mum onto some poor jackrabbit who made the choice to call and do their job? My answer is a resounding "NO!"

I plan on letting mum answer all future telemarketing calls too.
It's the one thing she enjoys lately.

Back to the reality of unhappiness with mum.
She's off the phone with the tax office, they hate it when she calls.
Which oddly enough ... makes me happy.