Of course you can join! Just come on and check in tomorrow when you see the check-in thread.
As Jane said, we're doing no salty snacks (chips of any kind, salted popcorn, crackers, etc.). Some are also continuing the no sweets challenge. That one is no baked goods, cookies, cake (unless it's a birthday cake and you can't avoid it!), ice cream, soda, etc.
The other part is a "drink 64 oz of water a day" challenge.
So feel free to do however many of those you like, and you can add your own too!