They all know about it (the young ones anyway), but I've never known them to do anything beyond some really light-weight stuff. Mostly telling silly, obviously-jokey stories in my experience.

But was April fool's a huge thing back home? Maybe I'm from a boring town, but all I ever saw were "light-weight" stuff

I've had students ask me about it. Some even seem to think it's a sort of holiday in America. I usually tell them it's just for kids where I live.

So how do you put saran wrap under the toilet seat on a squat toilet?

One thing I always do with my Freshman every year at the beginning of class is tell them that on April 1st we will have mid-semester exam, composed of the following: 10 essay questions (100 words each), all the vocabulary words that we have gone over thus far, extraneous speaking for 2 and a half minutes each, and also, the slang terms and idioms that we have covered. Then, I let them know that the school has given me permission to extend the test to three hours.

The look on their faces is priceless. Sometimes, one will figure it out and make a comment that it is April 1st, and I'll reply, "Yes, but I don't celebrate that in China. Sorry." By the end of the class, I'll let them know it's an April Fools thing. They usually get a pretty good laugh (of relief) from the whole charade.

I just did it yesterday with my Freshman, as we will be having class this Sunday because next Wednesday is a holiday and we are making up the classes this weekend.

Since Easter falls almost on April Fools, you could explain about Easter egg hunts, then send them out to search for Easter eggs you haven't hidden.

Note for April 1st:

Please don't play April fool tricks, YOU find them funny in the same way I find punching tricksters on the nose funny!