If you have blue blocks, some mounted games. Put something like a bottle or even a medium sized rock and move them up and down, bend in and out of Jump stands. Get poles/ fillers etc and make a 'Maze' that they have to steer round, it takes alot of effort getting it out but the ones I have taught seem to love it, then they can walk over the colours you tell them etc.. Hope this helps
The traffic light game, where red is stop, amber is walk and green is trot (provided the ponies don't get too excited).
Riding with their reins in one hand and getting them to steer different school figures or in and out of jump blocks like a slalom (depending on how good the ponies are at listening to legs for steering!)
Simon says, using things like ride with one hand on your head, whole ride walk/trot/halt; drill riding (kids seem to especially love doing the bit where the two halves of the ride cross at x on diagonals, like the cavalry do in displays, I usually start at walk then try trotting, haven't ever had any well behaved enough ponies for cantering!)
Teaching them jumping position and doing trotting poles.
Musical blocks if you have any of those plastic jumping blocks, a bit like musical chairs. Everybody trots around the outside and there is one less block than ponies, I usually don't have any music so just shout something silly to signal them all to ride to a block dismount and put their foot on a block. Then take away a block each time. Good for getting them to get back on themselves too!
Getting them to touch the letters on the fence/wall of the school as they are riding around with their outside hand, kmfh are the trickiest as cheeky ponies usually try to avoid corners, start in walk and progress to trot when they get them all in walk.
Set up a 'course' of poles so they can practice approaching them straight for when they start to jump.
Years ago my daughter had great fun with an instructor who started her off with £5. She put a pound coin between her knees and the saddle and every time she dropped one it would be taken off her £5 float - she either gained or lost at the end of the lesson!
This followed on by holding a tray of cups filled with water and she had to walk and trot, stopping and starting on command without spilling the water.
No stirrups, round the world, scissors, really quick commands of walk, stop, trot, stop etc all makes it good fun and best of all are gymkhana games