Frequently I find that there are dozens of technologies I want to learn, but really just don't have the time. As a list to myself (and anybody else who might care) of the stuff that I want to learn, but just haven't had the time, here's a short enumerated list:
JPA (Java Persistence API)
EJB Annotations (primarily for Hibernate)
And that's just the stuff I can remember off the top of my head as I write this. I'm sure that I'll add more later.