Yes, Bitcoin, but also about money, what it is and how easily it can be manipulated. Perhaps an inflation game. Would be great to play a game in class that would induce hyperinflation where other kids, that are consumers and businesses, would raise their prices and at some point somebody will probably come with another form of payment.

Also finances, how to deal with money and especially savings. At lastly technology. To get them excited about the technology behind it.