Rachel Caine's lateset novel in the Morganville vampire series.
This series is by far the best vampire stories published in the 21st century that i've read.
I am not yet finished reading 'Bite Club'.
But this is what goodreads says:
After discovering that vampires populate her town, college student Claire Danvers knows that the undead just want to live their lives. But someone else wants them to get ready to rumble.
There's a new extreme sport getting picked up on the Internet: bare- knuckle fights pitting captured vampires against each other-or humans. Tracking the remote signal leads Claire- accompanied by her friends and frenemies-to discover that what started as an online brawl will soon threaten everyone in Morganville...