When I was growing up, and before I knew what Mornington Crescent was, a friend and I came up with a game called Bob Barry.
The game works like this:
1. You say Bob.
2. Your opponent says Bob.
3. This continues in turn until someone says Barry.
4. You then argue over the non-existent rules, saying how that was or wasn’t a valid Barry. You could say they “waited too long after the last call”, or it was “too soon”, or just the classic “Nope!”
5. Spontaneously, during the argument, one of you says Bob, and a new round begins.
6. Repeat until parents get annoyed and tell you to stop. When this happens, you both win.
And with that: Bob.