When I met up with a friend recently he came bearing gifts. Well one specific, rather random gift actually, courtesy of his mother: Herman the friendship cake (though at the time he was not a cake, just a little bowl full of bubbly yellowish slop). I freely admit that I am hopelessly out of touch with the modern world and was therefore a little baffled as I had never heard of a friendship cake, but thankfully he came with a sheet of instructions.
It is basically a bit like a chain email (which I loathe) but using cake (which I love!). Herman is a living yeast mixture that you have to feed with various ingredients over a number of days, before giving four parts of the mixture to friends to carry on the chain, and turning the fifth part into a yummy spiced apple cake. A little research told me this is not a new idea, but based on a traditional Amish sweet bread that uses a sourdough starter. I have never had much luck with yeast-based things as I can never get them to rise properly, but because this evolves so slowly it is foolproof.
I can't deny I was a little dubious at the thought of the mixture sitting around for goodness knows how long in various random people's houses, but I got over it and the resulting cake was really yummy (and I haven't died from food poisoning yet), so if the mixture reaches you and you can turn a blind eye to the health and safety quagmire, then I recommend you try it!
If you like the look of this cake but have yet to be gifted a bowl of yeasty goo, you could always start your own - I found a link to the recipe here. And if you can't be bothered with any of that never fear as Herman bears more than a passing resemblance to this apple loaf cake, so maybe give that a try instead...