What is the setting, who is the crowd etc? Are they already familiar with blockchain technologies etc?
Try and sell the dream, open people's imaginations to the possibilities of what can now be achieved. Talk about a cryptocurrency without volatility, a solution to voter fraud (VOTE), a solution to domain squatting (DNS), fans supporting and owning musicians and their music distribution (MUSIC/Peertracks), cross game trading, betting and gambling without having to trust a third-party (PLAY). Don't get bogged down spending too much time on the technicalities, but do talk about the overarching concepts. Talk about how it empowers people. Talk about how we have huge decentralized teams all across the world, China, Argentina, US, Europe etc all working together on the same thing and how insane that truly is!
In the past, trying to explain Bitcoin to people I would always get stuck for about 15 minutes explaining proof of work and it turns people off because they just don't care. If instead I start by saying that we can now empower a child in Africa with a laptop and the internet to be the bank for his unbanked village, or how a hard working immigrant can work abroad and send back money to his family without a corrupt banking system sometimes taking as much 50% of that in fees the conversation always go very differently. Try and do this for BitShares, sell the dream and then show that this dream is becoming a reality because of all the amazing work of this community!