You can use any IRC client and connect to server botosaurus.com, or you can play in your web browser using the PJIRC Java Applet linked below.
It will take a moment to connect.
In the future I hope to customize the applet for the games. In the meantime, here is a hint to help you play bog.
To show the game board in a separate window while you play, double-click on the bot to open up a private message window. Then click on the 'window' icon which is in the upper right corner, second from the right. This will undock the window for private messages to the bot. You can type the "show board" command to see the current game board in this window. Also click on "Font" in the lower right corner and set it to Monospaced. If you arrange your windows then you will be able to see the game board in the private message window while typing words into the chat window.