That Fateful Night at Godric's Hollow
For the side of good, apparently a few people knew that Voldemort might try something, so why wouldn't some of the Potters' friends try to help (i.e. Sirius Black). I have a feeling that Sirius was, in fact, present that night as well as Wormtail, aka Peter Pettigrew. Sirius being there is due to the fact that he acted pretty quickly in going after Wormtail and then returning to the Hollow to try and take Harry, meeting Hagrid instead and lending his motorcycle. Wormtail would most likely have been there because how else was Voldemort's wand recovered for use in Goblet of Fire? And unless Snape was feigning ignorance about Wormtail working for Voldemort in Prisoner of Azkaban, it is quite possible that he might also have been there that night, but for whose side, good or evil? Don't forget that Snape is supposed to never have faltered in his support of the Dark Lord, but also was apparently (if my math is correct) already working for Dumbledore at Hogwarts when the Potters died. Snape assumptions aside, I strongly believe in my theory that Sirius and Pettigrew were both present that night and that there is a possibility that others might have been there as well.