- Napkin - http://my-wave-gadgets.appspot.com/wave/NapkinGadget.xml
- Whiteboard Gadget - http://vps.michaelrose.id.au/canvas.xml - Draw on a virtual whiteboard.
- Vector Editor - http://jsvectoreditor.googlecode.com/svn/trunk/wave/vectoreditor.xml - A cross platform collaborative real time vector graphics editor.
- Gravity (paid, I suppose)
- Plany - http://secowela.googlecode.com/svn/trunk/Web/Gadget2/hello.xml - Plany is a wave gadget for collaboratively creating a project plan and to keep track of project progress.
- Drawboard - http://wavedrawboard.appspot.com/waveDrawBoard.xml - Draw Board for Google Wave. More info and sample wave
http://www.google.com/support/forum/p/wave/thread?tid=3dcf3da6cd8165de&hl=en