Neil O'Brien and Richard North have set up a petition calling on the government to, after the one country given a vote rejected the treaty, abandon the EU Constitution/Lisbon Treaty. Sign it, get everyone you know to sign it.
Just because this Labour government have ignored the people's clear wishes on this matter so many times already doesn't mean we should stop making our opinion heard, loud and clear. The best way I've ever heard political campaigning summed up is Chris DeMuth's think tank slogan: "No one knows when the Berlin Wall will come down." There is always room for surprises in politics.
Besides, even if we can't stop this treaty we can make the process as painful as possible and, perhaps, turn a few politicos off the idea of further ceding power to undemocratic EU institutions.