I recently bought a large roll (100m!) of newsprint, so large scale pastings are pretty much imperative. First up was Falkor, the luckdragon from The Neverending Story. I was really impressed with how he turned out. I first found some pictures online, and traced it from the screen to a transparency, before using an overhead projector to get the image on to some newsprint I'd stuck up on my wall. Then out to the driveway to poster-paint the lines, and cut him out.
T'nealle and I stuck him along the edge of a carpark building. Neither of us are very good at heights, so it was quite exhilarating, but it turned out so well!
If you'd to see him, head to the Lichfield/Madras corner, and look up Lichfield (he's above The Bedford)
We've made a dedicated paste blog at PasteCity. I guess there are questionable legal issues regarding pasting, so check in there for future updates (though I'll certainly be letting you know about the other awesome projects as they unfold!)