If this happens, simply log out and log back in, and remember to wait. The main menu appears at the top-right of the screen. In addition to the large Log Off link, you're able to access these instructions, game news, your game list, pending challenges, the public chat wall, the player list, and preferences. Log Off removes you from the online users list and displays the successful logout screen. Instructions will display this page, which explains how to play.
News announces what games have been won or lost - handy for spotting cheaters.
Wall is the public graffiti chat wall. Only Lunatix subscribers may post public messages. Challenges is where you accept, decline, or cancel challenges. You can use the player list, the news log, or other places where player names appear to view information about a player and issue a challenge. Players who haven't logged in since their account was created probably aren't coming back, and might never see your challenge at all.