List all your desktop widgets here if this happens. Otherwise we all can just guess.
I used to get this problem a month back. I made some MOD's with the desktop icons background files few days before that and i thought that may have triggerred the issue. I reverted few MODs and restarted the phone. Touchwood the destop unresponsive issue did not happen to me after that. Did any of you guys did some MODs with your desktop files/images?