SPS 2010 Developer Dashboard...helps in troubleshooting

Stsadm –o setproperty –pn developer-dashboard –pv ondemand (or “on” or “off”)

This will put a small icon in the top right of your sharepoint page. Click it and it will display debugging info on your page all the way at the bottom. The cool thing is its activated by each person, by that if you click it, only you see the information.

Very useful!