June update: I had really gotten used to home-grown lettuce, but it looks like it's almost played out. Other spring crops are done, too. Summer crops are not ready to harvest, with the exception of three Hungarian Wax peppers. Some very brave bug ate a hole in one of the peppers. If you're tough enough to eat your weight in peppers, more power to you.
The corn is looking great, herbs are plentiful, and the brassica are coming along nicely.
Members of the cucumber/squash/melon family are not doing quite as well. I sowed seeds three weeks ago, and nothing has come up. I dug a few up to see what was going on, and I found the seeds had split open at the pointy end like they do when germinating. However, there was absolutely nothing inside the seed coat. Did these guys get eaten alive?
@Basjoos: Thank you for the data. For those who garden with a meat thermometer, here's another handy site:
Temperature effect on vegetable seeds - percentage germination