Well, my weirdest/funniest moment involved gaming CoC with two friends of mine.
The Keeper was a huge fan of H.P. Lovecraft, but really sucked at running RPG games; essentially we were all just doing improvisational theatre, not playing an RPG (since he never
used the rules).
Once he had us in the Dreamlands, and an apparation of Big C himself appeared.
My other friend, wanting to teach the Keeper a lesson about using the rules, asked if, in the Dreamlands, we could do anything we could imagine? He replies "Yes".
So my friend said his character would grow to the same size as Great Cthulhu, bend him over a mountain, and..... lets just say, "have his way with him"
We could all just imagine Big C's evil, slitted eyes growing to the circular saucers, and all his face tentacles spreading out in a 'scream'
I swear, we all spent the next 30 minutes at least just busting a gut laughing
Still didn't teach him a lesson though, he's never learned the rules to the game yet (but when we have nothing better to do, 'Improvisational Theatre' is a interesting way to pass the time).