It's short, but here's another excellent Good Omens cross, this one with Supernatural (not really unusual per se, but good enough I figured it worth a mention)
When Summoning Please Watch the Wording
by Ryuuza Kochou
Link: http://www.fanfiction.net/s/3547876/1/
When Summoning Please Watch the Wording
by Ryuuza Kochou
Link: http://www.fanfiction.net/s/3547876/1/