Tickets for UFC 108, the UFC's traditional year-end blockbuster event which takes place on January 2 in Las Vegas, go on sale next week. With injuries sidelining title-holders Lyoto Machida, Anderson Silva, and Georges St-Pierre, BJ Penn headlining UFC 107 in December, and heavyweight champ Brock Lesnar potentially unavailable due to an extended illness, UFC 108, generally one of the most-stacked cards of the year, could be left without a championship headliner