We stayed on camping Rhoon.
Things to do:
Visit the lighthouse and climb to the top. On a clear day you will have a beautiful view. The beach near the lighthouse is not safe but there is a nice cafe virtually opposite the lighthouse.
public outdoor swimming pool Molenkoog is nice with slides. Calluna is also okay but all indoors, quite small and expensive.
Boat trip to see the seals up close and actually walk on a sandbank in the middle of the sea with TX20 Orion in port of Oudeschild (near the bridge, give yourself plenty of time to find the boat as it leaves exactly on time, also need to reserve a place on tel 06 51044235 (dutch mobile phone)
Walking in nature reserve near beach pole 9 (check with locals as they may move about) to see wild Exmoor ponies and wild Highland cattle.
Horse riding also for people who are complete beginners or walk next to pony with child at Manege Elzenhof or Manege Kikkert.
You can go to de Slufter nature reserve to see the tides at work with a horse drawn carriage.
You can have a tour Monday till Friday at the Texel brewery to see beer brewing in action and taste the many local beers (weekend also but just tour whilst brewery is not working). Kids get local apple juice.
Pick your own fruit at local fruit grower diagonally opposite the Brewery.
Visit Ecomare to see abandoned and injured seals and find out about nature on and around Texel.
There are a number of small museums check VVV Texel website (tourist information).
Go to the beach near de Koog. The jellyfish are safe, although I would personally not touch them. Lots of seashells, small crabs etc. Kids can go fishing in rock pools.
Parachute jumping and sightseeing flights at Texel airport. Also tandem jumps for kids. There are discount vouchers in local supermarkets (free) or ask VVV (gives 10 % discount).
We were amazed that there was so much to do at such a small island and really enjoyed it.