Watch UFC 137 online tonight! 'Penn vs Diaz' live video stream/PPV details for Oct. 29

Expect the unexpected.

Ultimate Fighting Championship (UFC) will once again air an entire fight card TONIGHT (Oct. 29, 2011), this time it's UFC 137: "Penn vs. Diaz," which will begin around 6:30 p.m. ET with a live video stream on Facebook. Once the Facebook stream ends, two additional bouts from the undercard -- Donald Cerrone vs. Dennis Siver and Tyson Griffin vs. Bart Palaszewski -- will air live on Spike TV at 8 p.m. ET.

There are tons of ways to watch the pay-per-view (PPV) main card tonight, which will begin at 9 p.m. ET sharp, featuring the unlikely, but volatile, 170-pound pairing of B.J. Penn vs. Nick Diaz, in the marquee fight of the night.

You can call up Comcast or your local cable and/or satellite provider and order the PPV on your television. For the Internet folks among us, you can also stream the event on your computers using UFC.TV, Yahoo! Sports or UStream, among others.

And if you're really in a pinch, you can watch UFC 137 on your mobile phone via the Android Market or even now on YouTube.com. Remember, too, that there is a special UFC 137 closed-circuit show available if you are fortunate enough to be in and around "Sin City" this weekend.

However, if you need your UFC 137 results as soon as possible, for free, MMAmania.com will have complete results and live fight coverage, including round-by-round, blow-by-blow coverage of all the UFC 137 action before, during and after the event right here.

More details on the UFC 137 fight card, who is fighting who, as well as how to keep yourself updated, after the jump:

Main event:

170 lbs.: B.J. Penn vs. Nick Diaz

Main card (Pay-per-view):

265 lbs.: Cheick Kongo vs. Matt Mitrione
265 lbs.: Roy Nelson vs. Mirko Filipovic

145 lbs.: Hatsu Hioki vs. George Roop

135 lbs.: Jeff Curran vs. Scott Jorgensen

Spike TV "Prelims:"

155 lbs.: Donald Cerrone vs. Dennis Siver

145 lbs.: Tyson Griffin vs. Bart Palaszewski

Preliminary card (Facebook stream):

205 lbs.: Brandon Vera vs. Eliot Marshall

170 lbs.: Danny Downes vs Ramsey Nijem

185 lbs.: Chris Camozzi vs Francis Carmont
185 lbs.: Dustin Jacoby vs. Clifford Starks

To watch the UFC 137 "Prelims" on Facebook, (if you have a Facebook profile) simply "Like" the UFC Facebook page and check out the "UFC Live Streams" tab on the left-side menu.

Again, remember that MMAmania.com will provide LIVE blow-by-blow, round-by-round coverage of UFC 137, beginning with the Facebook prelims at 6:30 p.m. ET TONIGHT (Sat., Oct. 8, 2011). In addition, we will be your one-stop-shop for all the post-event coverage and highlights immediately following the show.

To get up to speed on all the news and notes for UFC 137: "Penn vs. Diaz," be sure to hit up our event archive right here.