Ted Cruz is currently on the floor of the U.S. engaging in a pseudo-filibuster of sorts, railing against Obamacare and hoping to stir up opposition against it. It is not a classic filibuster because debate is limited to a total of 30 hours on the motion to proceed on whether to debate Continuing Resolution 59, which was passed by the House. That CR would fund the government until December 15, but would also defund Obamacare.
Way back in March, the Senate did in fact witness an actual filibuster from Rand Paul (R-Ky.), who during a debate on the nomination of John Brennan to the post of CIA director, spoke for nearly 13 hours in an effort to bring attention to his concerns over a leaked Justice Department memo laying the shoddy legal groundwork on which the White House could build a case for the due process-free assassination of U.S. citizens.
Here's the first hour of that impressive talkfest: