Okay, I did the alleycat in New Haven. Here's what I learned, for those of you who ever do a search for "First Alleycat" and stumble upon this thread...
1. People might seem surly and cliquey before the race, but once you're rolling, you're all on the same team.
2. Communication is key for running red lights.
3. Be calm when planning your route; you will waste more time looking around than you will planning.
4. Be prepared for stupid surprises.
... and of course...
5. Carry more than one spare tube (flatted front and back simultaneously, had to carry the bike 3+ miles to the finish where I DNFed for not having 3 checkpoints. Fun anyways.)