Just a small blurb on TIMING for Events:
Set up custom countdown timers for things, it saves a lot of confusion. The nicest one I've found so far is
Time and Date's Custom Countdown Timer. Simply put in your location, and the day/time you want your event to end, and paste the URL into your listing.
Timezones are confusing at the best of times, this neatly avoids having to give a long list of time/dates for various places in the world and what local time things are going to be happening. Gaia is an international community, so don't forget that most of the world doesn't share your local time!
While we're on the matter of time, keep an eye on your thread activity during the days, and see when your most popular hours are - those are a good time to be running surprise flatsales or other short notice/duration things.
It's also a good idea to run longer duration events or sales so that more people get a chance to participate regardless of their timezone. While 10 o'clock speed flats might work for YOU, it means you might be excluding a good chunk of your potential customers.