You want to go on a sailing trip, but you need $500 for that. Buy and sell goods in a smart way to reach that amount as quick as possible!!!!
My entry for Ludum Dare 40 (theme: The more you have, the worse it is) is Salty Business, a sailing/trading game made in 48 hours in Unity3D. I've made everything myself, from the 3D models to the music and everything in between.
There are 5 islands with 5 weird characters on them. Every character has something to sell, and wants to buy stuff from the other islands. But how much will they give you for it? There is a lot randomised in this game. The position of the islands, the characters' home island, prices of goods, position and size of rocks and plants and the dialogue.