I think I'm going to keep writing in this blog this semester because I find I am integrating some of the 23 Things into my classes. If any 23Thing-ers are still reading, maybe they'll find this interesting and useful and then chime in with what they're doing.
First, while I use Blackboard, for two years, I have been trying to poke as many holes in its sides as possible. It's a great tool for gathering course activities and materials, but there is a real danger in putting all one's eggs in one CMS basket. I'm just slightly paranoid (don't all of us who teach with technology get a little paranoid?) so I have my course activities (this is English 101) spread all over the place but gathered in Blackboard. Then if something happens to Blackboard, most of my course is still reachable and usable. The only exception is the gradebook; it's only in Blackboard.
So, for example, instead of Announcements this semester, I have set my opening page in Bb to a blog (did you know you can have your Bb class open to anything you want, not just the announcements?), and while there is now a blogging tool in Bb, I have gone back to Blogger (http://kts-eng101.blogspot.com) So later in the semester, I'll explain RSS to students; that way, if they want to, they can subscribe to the blog and be notified when there are updates to it without having to log into Bb itself. (Note that this will screw up the course stats in Bb, but I've never found them very reliable anyway.) I've added a sitemeter to my blog, so I can see when (or if) students access it from outside Bb.
Secondly, I use an external discussion group (see, I really am paranoid). I was going to change to Bb's discussion group this semester, but then they had big problems with it at the beginning of Summer I, so I've kept Snitz Forums, a discussion group option offered at GCC. They are linked to a button in Bb, although students have to log in. But they're available directly, even if Bb isn't, and it supports RSS also. (So apparently does Bb's discussion group; you can subscribe to threads.)
I'll use Odeo or Evoca or Audacity for audio files (Wimba seems to be having problems already). While these third-party tools aren't always reliable either, I like having the options.
Finally, I create all my assignments on web pages and link to them in Bb. I don't have the learning unit management options, but it makes the assignments easier to share with colleagues too. One thing I dislike about Bb (and always have) is the closed-off nature of our classes in it. I think innovation and improvement most clearly thrive in the light of day.
But that's just me.