There are three mode for watching the video of UFC 121. First one you can watch live streaming online on your computers and mobile, from cable and satellite broadcast or at a bar near you.
You can watch all UFC Events in Smooth HD, LIVE in most parts of the world on UFC.COM. And you can catch the Unaired prelims shortly after the event is over. Apart from that, you can watch this event live streaming on yahoo sports after you purchase this pay-per-view match.
At yahoo sports, they will have high quality video streaming at 300k, 700k, and 1200k and only $44.95 gets you the live event plus 24 hours of unlimited archive viewing.
You can watch Weigh-ins and events like match of Lesnar vs Velasquez live streaming video on iPhone also. Click here to purchase from iTunes.
For cables and satellites broadcast, you can view it on fathom, ATnt, Bresnan, Bright house, Charter, Comcast, Cox, Direct Tv, Dish Network, Insight, Mediacom, thewarnercable, verizon wireless, inDemand payperview, Optimum and floTv live Pay-per-view match. Enjoy the evening with UFC 121.