Lots of discussion about the EU centres on the very significant effects it has had generally on the member-states, especially on their economic policies.
It could be interesting to focus the discussion at a more personal level.
What EU law has most affected your life, either negatively or positively?
Perhaps you're a fisherman who's been affected by regulations brought out under the Common Fisheries Policy, or a student who's been affected by EU law on freedom of movement.
Citation of the specific laws, with links where possible, would be great.