New School Based Club, Need ideas!

Use highjump kit for limbos - make sure cross bar is lightweight
Affiliate to British Schools Cycling Association for £20. If your Local Authority Education dept is affiliated (£50) it covers all local schools.
Use their Trix Awards scheme: it gives 27 skills, 9 each for bronze, silver and gold to aim at. I'm afraid you won't be able to gold yourself
Get hold of pallets and scafolding planks. Cut pallets down to width of planks, and planks to build improvised North Shore (at a very easy level) course. drill holes for large nails to connect them - not nailed together, make the holes big enough to drop the nails in
To improve their one-handed skills, use rings from PE kit and small rounders bat or similar to spear ring while you or other courageous volunteer is holding it.
Set up large circular target on ground, with rings on it like archery and get them to throw beanbags on to it and use team scoring competition
Get them to pass a bottle to each other while riding
Set target times for cone slaloms, say 6', 5'6", 5', etc (sorry, pre-metric era) by taking average of all of them less, say, 10%. Establish club records for any obstacle course you set up along those lines, etc., etc.
Contact nearest Go-Ride club for more ideas
Run skills relay races with teams of 3 or 4