What are any unique or particularly delicious simple syrups or sugar syrups you've made?

Recently, I tried a spritzer recipe that made a rosemary and citrus simple syrup, and instead of using water, it used a mixture of clementine and lemon juice.

I also recently tried a recipe for clementine preserves, where you prick them all over with a pin and then simmer in simple syrup. I panicked at seeing that 1:1 quantity of simple syrup written out, that a quart (or two?) of water required an entire 2lb box of sugar, so I used a small pot to only simmer 1-2 clementines at a time, rotating the fruit out and adding water. This sort of convoluted method took 4 hours of simmering for just 3 clementines, but when I reduced the syrup at the end, it was so delicious. It had a richer flavor that reminded me a little of honey. I did use golden sugar instead of white sugar, but my guess is that the sugar also caramelized over such a long time, in a similar way to Stella Cameron's toasted sugar.

Anyways, I'm wondering if anyone else has any favorite syrup recipes that aren't just sugar + water.