Rain dance

In computer science and hackerdom, the definition from the Jargon File 2.4.2 via FOLDOC (used by permission) reads:

1. Any ceremonial action taken to correct a hardware problem, with the expectation that nothing will be accomplished. This especially applies to reseating printed circuit boards, reconnecting cables, etc. "I can't boot up the machine. We'll have to wait for Greg to do his rain dance."
2. Any arcane sequence of actions performed with computers or software in order to achieve some goal; the term is usually restricted to rituals that include both an incantation or two and physical activity or motion.

Compare magic, voodoo programming, black art[?], cargo cult programming, wave a dead chicken; see also casting the runes.