City Bloxx is a Java game built into some of the latest Nokia phones, and is also available as a free game from the Download! service on certain Nokia S60 smartphones. It's a combination of an arcade game and puzzle game, and involves building tall towers as well as a spot of careful city planning to try and squeeze the maximum population out of the limited space you have to build on. It's also possibly the most mobile-friendly game ever given away on a phone.