Cheer! They're awesome in so many ways. Besides the typical lemonade, lemons are:
Aromatheraputic mood elevator
Negative energy absorber
Perfect thing to use for a hexing or blessing.
There are conflicting reports about when lemons were introduced to Sicily. There are reports of lemons around 300 CE, so say the scholars of such things on the internet. There are mosaics of lemons even earlier. Greece had lemons in the way way back, therefore Magna Graeca had it. Sicily was part of Magna Graeca. There are lemons on mosaics in pompeii. But I digress! On to the business of the night:
The lemon spell
Leland, a main source of this, seems to mix spells. You can find it in the early pages of Aradia. Here's my do-it-yourself version: At midnight, take your lemon and pierce it with happy things: colored pins in modern times, no black ones. Back in the day? Fragrant herbs? Piece of coral? Gem? Charge the lemon in your favorite way with your intent. In this case, it's for the blessing of whomever the intended is. The version in Aradia has an invocation of Diana, where it's Her power doing the work. You can do whatever you're comfortable with, but I do like asking Her Blessing.
If you use something for blessing, you can use it for the opposite. Instead of the above lovely things added, there would be rusty nails, dirt, black pins, bugs, and salt to name a few things. The ethics of hexing is another topic for another day.
This was a quickie post, but I will return to my cranktastic self tomorrow! \o/