Texas hold 'em is a pretty simple game. The trick will be shuffling and dealing the cards in a provably fair manner.
Discussion
"provably fair" is always a tricky one. you have decentralised sources of high-quality random numbers, but they are *published* sources, so by the time the system knows how to deal the cards, everyone else has that information too...
not that it necessarily needs to be proved as such. if you pointed a webcam at a lava lamp and generated entropy from that and advertised it as a lava lamp powered poker game, i'm sure a lot of people would find that very entertaining