I generally don't bother with April Fools' Day, mainly because I don't consider myself clever enough to come up with a good joke. Last year, though, I saw a few posts on jokes to play on the kids and someone online suggested putting googly eyes on everything in the fridge. I thought, "I have a whole jar full of those..."
I was worried it would take a long time, but it only took a few minutes to glue them on. The kids loved it! Kansas Dad told them I did it, but they didn't believe him and I stayed mum.
So if you're looking for something fun and easy that's unlikely to make anyone feel embarassed, I highly recommend a refrigerator full of googly eyes.