http://www.youtube.com/watch?v=6wy_mXuEsP0 Brent Hinds has twirled his Mastodong around by starring in a surprisingly well done commercial for Atlanta bar and restaurant Elmyr. We can only assume that Hinds truly enjoys their food and was happy to do it as I doubt a place that sells two kinds of PBR is flush with marketing cash. But Hinds is not the first person to put their metal powers to promotional use.
There is of course the "Rainbow in the Dark" Budweiser commercial Dio is famous for from back in the early 80s and the antithesis, Ozzy's Justin Bieber debacle. There's the execrable Metallica Guitar Hero commercial that's forced to end with an explosion it's so stupid. There is Mustaine and Megadeth doing one of the last lucid and helpful things in their career by promoting Rock the Vote. I also remember a commercial where a woman at a party pulls out a copy of Diabolus in Musica for a sight gag and resells it to some Europeans who say, "Slayer is best." Anyone have a copy of that laying around? And let's not forget Sepultura:
Now I know this isn't a comprehensive list and that there are probably many more, so go ahead and comment about Dimebag doing a Wendy's ad but after he died they destroyed all the footage or when Varg wrote a black metal version of "I'm a Pepper."