Also known as the Trespass Bill, H.R. 347 makes it illegal to protest near government buildings and grounds, as well as grounds where any politician protected by the Secret Service is visiting, or at any "special event of national significance."
Read the full text, it's short:

Federal Restricted Buildings and Grounds Improvement Act of 2011 - Amends the federal criminal code to revise the prohibition against entering restricted federal buildings or grounds to impose criminal penalties on anyone who knowingly enters any restricted building or grounds without lawful authority. Defines "restricted buildings or grounds" as a posted, cordoned off, or otherwise restricted area of:javascript:void(0)

(1) the White House or its grounds or the Vice President's official residence or its grounds,

(2) a building or grounds where the President or other person protected by the Secret Service is or will be temporarily visiting, or

(3) a building or grounds so restricted due to a special event of national significance.

The bill is as broad as hell, and the power is sure to be abused. Wherever politicians go, there are activists who protest and heckle. When I was at the Iowa Caucuses, people yelled "End the war against the poor" during Mitt Romney's rally, and his security dragged them out. Now, those people could be put in jail for up to 10 years.

Nice knowing you, First Amendment.

More detailed analysis at https://www.youtube.com/watch?v=2KAOn2dX8nw