http://appldnld.apple.com.edgesuite.net/content.info.apple.com/Aperture/061-6141.20090408.TR0r2/Aperture2.1.3Trial.dmg
http://minimal.cx/2008/02/15/aperture-2-trial-hack/
E-325-DJR-243-BDJ-316-XVX-435-OCN-FJ7-Z2RX

Open 0xED
Choose File -> Open...
Navigate to /Applications, then Aperture.app, then Contents, then MacOS, and finally choose the Aperture file and then click on Open
Ensure the editor is set to Overwrite mode (Edit -> Write Mode)
Enter 6d21b0 into the Offset box and hit Enter
Check the ASCII side of things and you should see the string performRequirementsCheck starting under the cursor
Replace the string with performLicenseCheck
Switch to the hex view, and erase the extra five characters (the Check string) with zeros
Save this file
Launch Aperture as you normally would