The cucumber spider would be be my first guess, and good call sara.

These are a European spider, and a very harmless orb weaver.

http://www.edderkopper.net/Bilder/Aranei...

Another possibility is a green lynx spider:

http://wallpapers.pupazzo.org/animals/Gr...

This is where knowing your location helps.

Maybe Araneus Cucurbitina, I'm not sure though and I'm not an expert, just like spiders.