I always like seeing how visual programming is implemented. The last few years I have seen many node based versions. Basically think of nodes as rectangles and then lines connect the inputs and outputs from the nodes.
Here is one that is different.
http://gamemakertutorials.com/game-maker-genres/gamemaker-platform-game-part-1/I think the node based is better, but I think features from the above could be used to find the node types you want to use in a node based system. Sort of a combination of the two, the best of both worlds.
