Dang! Here are two incomprehensibly outlandish ideas I had while stuck in construction traffic today: Professor Snape IS Regulus Black
That is pretty outlandish. I reread GoF, and have about ten pages left on my OOtP reread.
I think Snape is Snape, but there was something I read in OOtP that caused me to wonder if Dumbledore is really dead-I've thought from the get-go that Dumbledore IS dead. It wasn't Bellatrix Le Strange's comment that you have to really mean the unforgiveable curses, it was something else. (which I forget at the moment, but will look up after I finish the whole book)
The three things that keep puzzling me are: 1. the reference in one of the books (Goblet of Fire, I think) to how Harry thinks a "look of triumph" crosses Dumbledore's face after he learns that Voldemort now can touch Harry without harm; 2. the two way mirrors that Sirius gave Harry: I think those have to play some role later, don't you? Otherwise they were rather pointless, since Harry didn't think to use them to check on Sirius at that critical juncture in Order of the Phoenix. And 3: where have we seen the name "Peverell" (from Marvolo's ring) before? I have been looking. The closest I can get is Nicholas Flamel's wife "Perenelle" so maybe that was what I was thinking and the Peverell name was only introduced in Half Blood Prince. But the Peverell name keeps nagging at me somehow.
I am also wondering if somehow Snape is related to the Potters (specifically Lily Evans) on the Muggle side.