I dream one day of having a digital card game, not unlike the collectable card games that are out there but without the need to pay for booster packs.
Ideally it would have some method built-in for designing your own cards with some kind of point-buy or other formulaic method.
And yes, I'm thinking of Kobolds in Space, which is already simple enough for the characters/items/etc. to be card based.
I confess I first started thinking about this when Ellie took the ruleset and built this glorious adventure generator.