One problem with learning to ride a skateboard is simply maintaining balance. Staying on the board is the other problem, but again it comes down to balance. If you could solve the former problem, the latter one would be less of an issue.
Now it seems that a few people have tackled the problem by incorporating the same technology used in the Segway scooter into a deck, which was unveiled at Maker Faire 2011. The question here is whether this things is technically still a skateboard or just a revised Segway with a flat board?