Sales training games & activities

I’m a sales trainer and I’m looking for activities that I can use when working with clients who need to understand how to Upsell / Cross-sell.

FYI, I use this McDonald’s example to explain it:
Upsell – Would you like to go large?
Cross sell – Would you like fries with that?

I don’t mind about the duration, whether it is suitable for small or large groups or whether props are needed or not. At this stage I’m just looking for some ideas/inspiration!

Thank you.