If an invite to Evolve's upcoming closed alpha is your white whale, you've got two (constructive) options: Play a round of Evolve at 2K's PAX Prime booth (Level 4, booths 814 and 1414), or stalk Evolve's social media channels and the Turtle Rock forums. Hunting game at Prime will earn you an invitation to register, but "additional chances" can be tracked down on Twitter, Facebook and the forums.
Unfortunately, putting down your first monster is going to be a lot like real-world hunting – the alpha's reveal post doesn't specify when the event will begin, so you'll need to keep a determined watch on the aforementioned channels or your inbox.
The upcoming expedition will follow a separate alpha from July which must have thinned out Turtle Rock's monster supply, as Evolve was rescheduled for February 10, 2015 days after the alpha went live.