If you feel like you haven’t had enough time with the Halo: Reach beta yet, you have a little bit more time to kill one another before having to go back to one of your other, lesser Halo games.
Speaking to Joystiq, Bungie’s Brian Jarrard has nailed down the exact date and time that the beta will be shut down. That would be Thursday, May 20th at 10am PDT. The beta was originally expected to conclude today.
No explanation as to why but, really, are you going to look this gift horse in the mouth? If so, you’d better do it quickly before you run out of Reach time.