A long long time ago, I acquired a copy of a game called "Alley Cat". It was a fairly simple game, running under Dos. But when I showed it to my daughters, who were at that time aged several, they loved it, and the beep-beep tune of Alley Cat could be heard very frequently.
Something made me think of it today, and I used Google, And to no great surprise, it's available now. You can run it via your browser.
So, knowing that they read my blog occasionally, I thought I'd mention it here.