I don't understand why the yields (each is a data point?) you list for different types of bonds are referred to as a curve.
The maturity vs. yield data is often display as - and referred to - as a curve. Somewhere on the web there was (and maybe still is) an applet that shows how the Treasury yield curve has fluctuated over the last 40 years or so. It's a dynamic beast. Since I'm fond of VG muni funds, I track that particular yield curve.
Vanguard's muni fund yield curve for 11-21-2008:
+ money market: 1.25% <-- continues to drop like a rock
+ short-term: 2.72%
+ limited-term: 3.23%
+ intermediate-term: 4.19%
+ long-term: 4.62%
+ high-yield: 5.40%