There are no scheduled times for chatting but folks are welcome to visit the main chat room site any time (you'll find it under the "Around the site" menu on the right). You can also create your own chatroom by clicking on "Create a chat room" under the "My Tools" menu over to the left (you must be a member and logged in to do this). Make sure you add it to your favorites list so you can find it again once it's made. Then you can invite your friends there to talk with you in real time.