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CHALLENGE: Bring 50 new people into this campaign in time for the President's 50th birthday. Choose one or any combination of the organizing activities below—we'll track your progress for you after you register. Once you get to 50, you'll automatically be given a chance to be one of four supporters who will join the President for a birthday celebration in Chicago next month. For a complete list of ways to enter and full details, click here.

Right now, thousands of supporters around the country are working to bring 50 new people into this campaign in time for the President's 50th birthday. They're making calls, collecting "I'm in" commitment cards, hosting events in their neighborhoods, and asking friends to pitch in what they can. Once they bring in 50 new supporters, they'll automatically be entered into the running to join the President in Chicago for his birthday celebration on August 3rd.

You can still join them in helping to grow this campaign. You can also sign up for the chance to attend the President's birthday celebration here without getting involved. But if you get the chance to meet him, you'll have a lot more stories to tell him about how you've helped build this campaign if you put in the time to bring 50 more people into it.

By clicking the "Enter Now" button, I agree to be bound by and comply with the Official Rules.

No purchase, activity taken on behalf of Obama for America, or contribution necessary to enter or win. Contributing, volunteering, or making a purchase will not improve chances of winning. Void where prohibited. Entries must be received by 11:59 p.m. on 7/28/11. You may enter by taking fifty "actions" on behalf of the campaign including gathering "I'm In" commitments, receiving contributions from contributors on your grassroots fundraising page, or by inviting attendees to you event in accordance with the requirements set forth in the Official Rules. Alternatively, visit http://my.barackobama.com/50for50-alt to enter without volunteering. Four winners will each receive the following prize package: one round-trip ticket within the U.S. to Chicago, IL; hotel accommodations for one; and admittance to a birthday party for President Obama on August 3, 2011 (approximate retail value of each prize package $1,050). Odds of winning depend on number of eligible entries received. Promotion open only to U.S. citizens, or lawful permanent U.S. residents who are legal residents of 50 United States, Puerto Rico or the District of Columbia and 18 or older (or of majority under applicable law). Promotion subject to Official Rules and additional restrictions on eligibility, available at http://my.barackobama.com/50for50-rules. Sponsor: Obama for America, 130 E. Randolph St., Chicago, IL 60601.