The ebuild x11-misc/mgm/mgm-1.1.ebuild contains a wrong homepage. The old line is: HOMEPAGE="http://www.xiph.org/mgm/index.html" But it must be: HOMEPAGE="http://www.linuxmafia.com/mgm/index.html" The SRC_URI also wrong. It should contain the link http://www.linuxmafia.com/mgm/mgm-1.1.tgz.
Fixed in cvs. Thanks for reporting.