The Monkey park between Los Cristianos and Guaza is a great and cheap day out for adults and kids alike.
I took my cousin's two kids in January (well you have to show willing
) and we had a great time. It's €10 for adults and I'm not sure about kids but seem to remember it was either €5 or €6.
The park is a lot bigger and more interactive than I thought it would be. There are many places where you are in with the animals and can feed them by hand.The kids really enjoyed it. Almost as much as I did
Here is their website.