A lot of information regarding X-Men: Days of Future Past's Sentinel threat has now become available thanks to a rather gorgeous looking viral website for the film's Trask Industries, which just drips with casual hatred for mutants.
There's a lot to take in, but my favorite tidbits involve info on Trask's creepy Mutant Detection Device and Inhibitor Collar. A lot of this stuff will probably go by quickly in the film itself, so it's nice to have a site where you can soak in all the details. While I'm still not very excited for X-Men: Days of Future Past, the effort put into this viral site is impressive. More importantly, the site definitely conveys a terrifying world for mutants.
In addition to the above video, there are some great photos of the film's not so great Sentinels, which you can find below. But you should really visit the site itself to get the full effect.