I didn't know you could make sculptures out of Post-It notes, but I swiped a link from The Presurfer that led me to a very cool collection of 16 pranks, sculptures and murals made from the humble sticky note. I also found an almost finished Post-It version of the Mona Lisa over on Flickr.
Ever wonder how (and why) Post-It Notes were invented? Evidently it was part glue failure, part church hymnal.
The best Post-It Ad of all time, I think, is this classic on "how guys use Post-Its":
I prefer virtual sticky notes, as they never fall off or get lost or otherwise vanish. The maker of Post-It notes sells a digital version of their famous product, but you can also get some freeware sticky note programs out there; check out DigiNotes, Floating Notes, Hott Notes, StickIt or Sticky-Notes. Remember the freeware caution: always scan free downloads of anything for bugs and other threats before dumping the programs into your hard drive.
As for the art of Post-It notes, my favorite is a performance piece that took 280,951 sticky notes to create: Eepybird.com's Sticky Note Experiment (if you click on nothing else in this post, look at this one.)