We've got a fair number of new starts in the kids' class, so a night on the focus mitts working various punches is always a good start. All grades can do that too, and it's something everyone can benefit from.
The trick to the kids' class is don't let the chaos take over. They need some leeway, but not too much. They need a bit of order and discipline, but not in the old fashioned marching about sense.
Pad work is great for training in a sensible way without being boring or too out of it. Especially when the training is structured. So I stole an idea from Western boxing.
Each punch has a number. You make up combinations of numbers, calling out the numbers for the students to practice.
Start with the front hand first.
1-2 lead punch / reverse punch
1-2-1-2 lead punch / reverse punch doubled
3-4 lead hook / rear hook
1-1-2 Two quick jabs followed by a powerful back hand shot
1-1-2-3-4 Repeat, with hooks on the end
1-5-6-7 Lead punch, shuffle stance into a right side kick, land into a mid section reverse punch
The sequence ends in the opposite stance so now you can repeat it.
We did each little combination on the pads, then we strung them all together into one big routine. It was great fun! In fact I used it with the senior class too.
You can take this idea anywhere you like. Codify various punches, strikes, stance changes and kicks. Make small combinations, then link them together. Want to practice at home? Use it as a "shadow boxing" routine, or "kata".
Write down your favourite routines, but you don't have to try to remember them all the time. Create them for what you want, then swap them for others. You might find some central themes cropping up, or some particularly useful sets that really develop basic skills. Why not add a couple to your syllabus as "skill builders"? Or just use the concept in general. Or have your students develop their own variations to suit their own needs.
Then of course train with a partner. Attacker goes through the sequences, defender responds. Get an attack-defence routine going. Next step is to break the rhythm by adding in "in-between" techniques such as "random elbow attacked after each combination", or intersperse the sequence with other activities, such as a free exchange of kicks, clinch work, push hands or anything else.
You can train at different intensities, solo or with a partner (or more than one partner!), introduce weapons work, sparring drills or other pad drills based on the pattern.
It's just a way of working basics and combinations, developing basic movement. Go with it, then discard it as you need.