I don't think that there's such thing as easy summoning spell. By summoning other being (from my point of view) would require something to bind them. Something to lure them.
And maybe their name too. For instance, you wouldn't be able to call someone without knowing their numbers, can you?
But, i'm not that good in summoning spells.. So, if you somehow discover how to do it more easily, let me know, ok?