Gadgets can increase the level of interaction between you and your contacts. You can insert gadgets from either the Gadget Gallery or by inputing the address of the desired gadget.
1. Go to Google Wave and login to your account.
2. Go to the top of the middle column and click the New Wave button to create your wave.
3. Select the newly created wave and click inside the body of the message.
4. Go to the menu in the upper-corner of the screen.
5. Click Debug and select Extensions.
6. Select Add Gadget from the resulting menu.
7. The Gadget Gallery will open. Select the desired gadget from the gallery or go to the bottom of the Gallery window. Use the Enter the URL for a gadget you want to add textbox to input the URL of the desired gadget and then click the Add by XML button.
The selected gadget will appear in the body of your wave.