typing sudo in the alt-f2 run applications dialog box and then the program name or command freezes the system or just typing sudo and hitting the enter key, both actions also shuts off any sound/music as well if any are playing and where at least/most the keyboard & or mouse (mouse can only move around can't select anything) only works to allow a ctrl+alt+backspace if not and one has dontzap in the xorg conf then the only way out is via the powerbutton on the computer. Gksudo seems to be unaffected by this and does NOT cause a freeze up of the system. This occurs if by defualt and left unchecked "run in terminal" is unchecked and one just presses the enter key on the keyboard.
YES I did a full install of Gutsy and have all updates up to when this bug/freeze was filed.
i did the xprop | grep WM_CLASS and it identifed the run dialog as gnome-panel if it is NOT the cause please put it into the right category wills ya :)