Microsoft wants everyone possible to play around with the Age of Empires Online beta, so it's offering anyone and everyone the chance to get in on it before it closes to the public.
The 48-hour period starts today and runs through Saturday and to get your beta code, click this link now.
Afterward, you will be prompted by the Games for Windows Marketplace to sign up for a Windows Live ID if you don't already have one.
After you sign in, you can download the beta files and start playing right away.
System requirements are listed through the link.
Edit: We said in the original article that, "The beta ends on Saturday at 9.01am." This isn't the case. Sign-ups end on Saturday, but the beta itself will continue beyond this 48 hour promotional period.