If you get really annoyed by immature people don't come, the maturity level isn't all that high (there was a random guy running around in boxers with music and I lost the game every five minutes. Literally). Also, if you're staying in a hotel, book it right now. I mean this minute. Rooms are usually booked the minute the dates for the next one are released. Just had to get that out of the way.

I love Otakon, simply because it was my first con. There are tons of people, and lots of awesome costumes. The Dealers Room is HUGE, and there are so many things to buy. Once it's over, you'll be tired, but ready for another one (but your wallet won't). They'll be a ton of Light's though, just a warning.

I don't know anything about the LARP except they don't have cosplay chess.