It looks like most of my Google Gadgets are temporarily unavailable due to my exceeding the bandwidth allowed by Google Pages. I wish that there was a bandwidth meter available so that I could have seen this coming.
I’m going to have to find another place to host my gadgets.
Update: If any of the google gadgets are not working for you, you should be able to get them working again by adding them to your page from this site. This will retrieve the gadget from the new location.