Stattoo rocks. Think of it as a transparent dock where you can put semi-transparent information like time, iCal stuff, temperature, battery life - all this stuff.

I can see how it would interfere with your Dock, but the Stattoo is movable (you just have to bring up the Stattoo preferences to move it - so you can't move it accidentally).

I'm sure I could think of neat modules to write with Applescript or Python - actually, there's an idea: a module that lets us run a script (be it shell script or Applescript) every N minutes, and display the results. Yes, I sent this idea into Panic.