On our recent Lake District holiday, I took a series of photos encompassing the Castlerigg stone circle. I wasn't intending to do anything with them; I was just testing out my new camera. However, after I got home, I wondered about trying to stitch them all together into a single panorama. A bit of googling later, I downloaded Hugin.
It took me a few goes to get things working -- mostly, I think, because I hadn't been thinking of taking a panorama originally, so had moved a bit between some of the shots. Still, after playing around with control points, and masking out the people, and removing the shots with the most parallax, I manage to get a panorama that includes nearly all the stones:
These are the actual photos that Hugin stitched together:
The panorama has a slightly wobbly horizon near the secondary circle, and there are some artefacts in the stitching. But given the poor quality of the original photos for this sort of thing, the result is amazingly good. And the ability to mask out certain areas (here, people) is really useful.
And all this with open source software that I downloaded of the web with the click of a button!