I have an easier argument. Come up with a half-interesting problem and ask them to solve it with and without jq. they will immediately love JQ. We snuck it in because we wanted the .load functionality. And I assure you everyone immediately fell in love. After that it was not long until cool animations started to appear. People started saying "hey whats that really cool thing you did with the UI in that app, how do we do something so cool too?"

The niceness of just DOM manipulation + some ajax simplifiers + animations = awesomeness!