I my self came across the word after watching RHCP and took it on as a way to describe the pain i got from taking a painful hit into the shin during skateboarding.
Soon after it got bigger, but i ain't saying that i came up withit seaming i started saying it back when that video came out...
Shin dig - A loudly shouted word when in pain while out skateboarding/BMX'n
A shindig usually does not escalate into a large full scale party because it is meant to be a low key night, avoiding any complications such as cleaning up vomit, unwanted guests, picking up trash the rude guests leave lying wherever they drop it, putting everything back in its proper place, eliciting attention fom neighbors and local law enforcement, etc.
"Dave's having a few people in Friday night... sortof a shindig - not really a big party or anything"
Verb: to shindig or not to shindig? that is the question.
Noun: holy guacamoly, we got chips! good thing we came to this here shindig!