Hi Hoopman
I stayed in Calpe about 3 years ago. We found it a bit quiet at the time, but it would be perfect for families. The beach is lovely, very clean and safe. There are lots of nice restaurants and bars in the area. If you rent a car you can explore the nearby towns-Altea seemed nice and I think had a market at weekends. The drive along the coast into Benidorm is very scenic. Benidorm might be worth a visit during your holiday if you fancy something a bit more hectic, but Calpe is definitely a nicer place to be based. The kids would probably enjoy Terra Mitica, the theme park near Benidorm, and you might even enjoy it yourself!
Hope this helps