It is fascinating what some people will come up with when their minds are racing. Sometimes I wish I could think of these ideas first. I think I do come up with some crazy ideas and blow it off as preposterous only to find out someone has created the idea I blew off as preposterous. Perhaps that is what Anna Gram's did, except she actually produced what is probably very useful to some.
Anna Gram's artsy Citrus Clock combines the magic of stellar design with basic science in order to create a timepiece that's powered by lemons! Reportedly, a single juicy lemon will keep the seconds ticking for two weeks, which is not bad at all.
Check out the website for more info.