Due to the bizarre nature of time travel, one of the realistic joys is the fact that no amount of planning or preperation is really needed when holding a convention. A person can get to any such convention from any point in the past or future, so any given convention is a suitable one.
The flip side of this, however, is the fact that once it's been established, you only ever really need one convention. The difficulty then becomes one of location. Where to hold it, rather than when. A neutral ground.
Here and Now
It is no surprise, then, that the site of the first Time Traveller's Convention came about accidentally. A certain pocket dimension (no one is quite sure about whether or not this pocket dimension has always been there, or if it was accidentally created) was a frequent crashing point for scientists and mages who caused terrible accidents in their time experiments, and also a point for pan-dimensional entities who got lost during their mysterious wanderings.
These entities swapped their stories, their secrets, and their tips. Initially they swapped their data because they needed a way out. As more and more people crashed in this pocket dimension, and as a few people even began to come back to check in on seeing who was there, it moved from being an unfortunate hapenstance to being the hippest place for any time traveller to hang out.
Welcome To The Convention!
So saying, welcome to the first Time Traveller's convention. You might have been here before, but it was probably a future you. Unless you remember it happening, in which case it was the past.
We have any number of workshops going on constantly. We also have several merchants selling their time travel wares. Some which cost an arm and a leg, others which can be bought for a story or song (the first example was a metaphor, unless it's at the table of Dr. Frank N. Time.)
And if you came here by accident rather than intent...welcome to the club! Feel free to hang around for as long as you'd like. You'll be just as likely to get back to when you need next year as you would next minute. There's plenty of sympathetic faces capable of helping you to find your bearings.