Some of you might know that I'm writing a jQuery book for Manning called jQuery in Action. It's pretty awesome, and includes a bunch of labs and exercises that are unique to it. My coauthor is Bear Bibeault (pronounced Bee-Bo), who coauthored Ajax in Practice (and hilariously enough, Prototype and Scriptaculous in Action).
Anyhow, check it out. If you buy now, you get the early-access chapters, which is the equivalent of the PragProgs' beta book stuff. We've already released betas of chapters 1-8 (of 9), so there's a lot there.