hp_halloweensign-ups are open here on LJ until October 10 with an October 29 due-date. It's a 200-word drabble exchange, which is easy as pie and a great way to get your feet wet in exchanges.
I've done it every year and had loads of fun, and I hope you will join us! I plan on cross-posting here if the mod gives me the "go", which I'm pretty sure she will, as I did it last year.