If you have children, playing with the sand on a sandy beach (Tsambika, Agathi and Faliraki just to name few) can be fun and a creative way to spend some time with them. There are more possibilities than just the ordinary sandbox.
With the proper amounts of sand and water the mixture will became adherent. You can built mountains, castles, canals, bridges and even sculptures. Covering someone up with sand is another popular beach activity.
A very popular way of building on the sand is dribbling where you let slowly drip the mixture of water and sand from above. The resulting abstract effect can be described as Gaudi-esque. More elaborate results can be achieved using pieces of wood or even pebbles as a sub frame.