A fun feature on CardRoom.com is the ability to throw
chips to get another player's attention. When you throw chips, it makes the
"chips clinking" sound on everyone's computer (assuming they have the sound
turned on) and displays "[username] throws chips" in the chat window. This
feature is typically used to get another player's attention when it is their
turn.
To use this feature, while seated at a game table, right click on your
portrait. Then select the "Action" menu item and select "Throw Chips".