Amongst other things, their laughter is a response to new discoveries they make each day. Presenting the grammatical structure in a child's context, with humour Characters are extremely helpful when presenting points of grammar for the first time. In Jennifer Seidl's Grammar series, a small, friendly alien called Trig provides an opportunity for children to relate to a character who, like them, is struggling with some of the idiosyncrasies of the English language. You can create your own characters to suit the English you're teaching. Children enjoy making up silly names and giving characters a personality.
Parts of speech can be 'people' - try having a character called the Present Simple.
He brushes his tooth. Use a soft toy or a puppet as a character. This can be particularly useful and memorable when you're teaching prepositions. Let the children give it a name and take turns to put the toy in various places round the classroom. Sometimes it's difficult to see how a grammatical topic can be made humorous but with a bit of imagination, almost anything can.