Now last week, there was more progress. Down below 171 for the first time in a long time, which puts me over 20 pounds lost in total. Now, I may not reach my goal (I'd need to drop 10.8 pounds in five weeks, which is possible but not reasonable given my progress to this point), but I've definitely made a significant difference so far.
I ended up agreeing to play on a team of four for the second volleyball session, which means that I'll get a bit more exercise than I did the first session on a team of six ... that won't hurt, even though it's basically going to be one hour per week.
More progress to come, hopefully. Next week would be the end of the second month of weigh-ins, so I've got one month after that before the end of the main part of the contest. The second part is technically maintenance, although the prize at the end still goes to the greatest weight loss over the entire time. (I think a better prize would have been to lock in people's weights in the August weigh-in and make it truly about maintenance; they could then reward everyone who weighed no more than they did in August. Of course it doesn't matter now that I'm not eligible myself ...)