Forget a condom... I mean that's important and all, but the worst thing for me is to be listening to Sean Hannity or Rush Limbaugh (opposition research) and hear them rake a liberal caller across the coals for not knowing the facts. On the rare occasion that either of them will allow a caller with an opposing view, it is important that said caller not only be passionate but knowledgable on the issues... No one looks more foolish than a person who fights so passionately for a cause they know little about, so don't get caught out there.
That being said, the one attack you should be able to counter if you are an Obama supporter is, "Name one significant accomplishment he's had as a Senator". Most times this stumps the passionate, uniformed fool, but no longer. The answer to the question is:
The Lugar-Obama Non-Proliferation Act
This law, authored by Richard Lugar (R-IN) and Barack Obama was passed in 2006 and signed in 2007 to secure loose nuclear and conventional weapons around the world and keep them out of the hands of terrorist.
The Coburn-Obama Transparency Act
This law (which John McCain co-sponsored) was the work of Tom Coburn (R-OK) and Barack Obama. It provides that all federal contracts be made transparent and available online to the public. A nice bit of sunshine into a shadowy world. You can see the results here at http://www.usaspending.gov/. But to go deeper into how much more legislation he put forth that was never passed, as well as his entire legislative biography go to: http://obama.senate.gov/issues/ethics_and_lobbying_reform/
Relief for the Democratic Republic of Congo
Authored, sponsored and introduced by Barack Obama, this legislation provided increased foreign aid and relief to the country, and directed the U.N. Ambassador to press the U.N. Security Council for stronger peacekeeping forces in the region.
This is in addition to over 800 pieces of legislation he put forth in the Illinoise Senate. Don't get caught out there...