I collected stamps as a kid. I loved the colors and the countries and the little bits of art they carried with them on their journeys.
Those feelings still lurk inside, even though I haven't licked any gummed papers in a long time. (Do they even still use those little folded gummed paper bits to stick the stamps in the albums?)
Artistamps (artist-made postage stamps) tap into all those feelings. You can make them as simple or as complicated as you wish. They can simply be a piece of art in stamp form, with or without a denomination. Or you can create a whole postal issuing authority. Of course, that's what I've done...
My postal issuing authority is an imaginary island nation called Craneland. It's located in southern Lake Erie, near the other islands owned by the US and Canada (Pelee, Middle Bass, etc). It's similar to the other Lake Erie islands: there's a winery located there, a bird sanctuary, farmland, several marinas, etc. It's named after the rare Blushing Crane which makes its home on the island.
Along with tourism and fishing, one of the main sources of income for the island is the postage stamps they issue. The most recent one (above) celebrates one of the pleasures of late summer, the homegrown tomato, specifically an heirloom variety. I might just make fresh tomato sandwiches (thick slices of homegrown tomato and mayonnaise on good bread) an official national dish... yum.