Drip sandcastles are fun to make and they don't require any tools. You just take very wet sand and put it in your hand (could add more water, too), and then drip it into piles until all the piles look like a castle. It's a surreal look and very satisfying. Here's a link to someone explaining how to do it and a wikipedia link with a photo of a bigger dripped castle.
Anatomy of a Drip Castle*
[ame=http://en.wikipedia.org/wiki/Sand_art_and_play]Sand art and play - Wikipedia, the free encyclopedia[/ame]
Anatomy of a Drip Castle*
[ame=http://en.wikipedia.org/wiki/Sand_art_and_play]Sand art and play - Wikipedia, the free encyclopedia[/ame]