Here's a dialog activity my ex-CT used a year ago, that I'm just getting around to sharing.
It takes a bit of work.
She made sandwiches with different sauces. Some were really hot, some were just disgusting (on purpose), some were peanut butter, honey, and jelly.
She cut them into little squares and distributed them to the groups. They had to blindly taste one and use this dialog:
S1: Would you like some?
S2: Yes, please. (takes a bite and then...) Mmm...This is good (if it actually is) or This is bad (if they don't like it).
S1:Would you like some more?
S2: Yes, please (if they actually do) and No, thank you (if they don't).
Or you could do it one student at time, but found this to be time consuming and one sided.
I hope someone can use this.