A interesting way to spend a couple of hours (and also would be a perfect thing to do if it is raining) is a visit to the Almuñencar Aquarium.
It's a bit expensive at adults 12 euros children 9 euros. It has a long glass tunnel where you can get in amongst the sharks, rays and other big fish.
At the start there are serveral big tanks, I particularly liked the rays which are about 30cm wide, they roll on the surface as if to say hello and you can see their mouths. Fascinating.
Times and prices
http://www.acuarioalmunecar.es/info.php?info=hPlaza Kuwait s/n - 18690 Almuñécar (Granada) Tlf. 902 109 835
Another thing to do if it is raining is the caves at Nerja.
There is a massive series of caves filled with stalegtites and stalemites.
More info.
http://www.nerja.org/turismo_ing/tur_cueva.htm
Almuñecar has a castle which is a worth a visit.
It has great views of Almuñecar.

Adults 2.20 €
Children: 1.50 €
Tue-Sat 10.30 - 13.30 / 17.00-19.30
Closed on Sunday and Monday
Click here for more pictures.
http://www.flickr.com/search/show/with/3218251829/?page=2&q=castillo+almu%C3%B1ecar
Walk all the way from Almuñecar to La Herradura along the coast which would take about 2 hours.
Then eat at one on the beach bars for example the Gaviota.
If you are tired you get get the bus back to Almuñecar.