Last year I made a deck of custom playing cards. These are related to "transformational playing cards" that were popular in the 19th century and were different than regular cards because the pips were incorporated into some kind of design. Mine were designed to be an homage to science fiction - Clubs = retrto sci-fi, Diamonds = slick high-tech sci-fi, Hearts = steampunk, Clubs = cyberpunk.
I'm not a traditional artist, but I was able to build the elements of the cards in Second Life (a virtual community). This involved a lot of work building each of the small elements used in the cards (the little robots, the suit "pips", etc.), styling the avatars to fit the look and feel of each suit, making the textures for the frames and backdrops, etc. It took about 2 months to build and design and about 2 months to do all of the screen capture snapshots, then an additional month or so for the Photoshop work.
For example: the Ace of Shovels
Once everything was done I had the deck printed on Moo cards and they came out wonderfully! Since they are Moo cards and on coated card-stock they are even playable.
Link to the Flickr Set of the full deck: http://www.flickr.com/photos/arystopics/sets/72157625699939891/