In Judaism and Islam, Shiva is a period of grief and mourning after the death of a close relative. While non-Jews are also sad when someone dies, Jews cloak this in ritual to note their part in a community of the excessively serious. The rituals disrupt normal activity, so the mourners are described as sitting shiva. "Laying-about shiva" or "lolly-gagging shiva" wouldn't sound as attractive.
Shiva is based on שבעה, the Hebrew word for seven. As there are a lot of threes in the rule for awarding a save to a baseball pitcher, there are a lot of sevens in the rules surrounding shiva. This is because Judaism is superior to baseball.
- There are seven classes of people thought of as close relatives: parents, children, siblings, spouses, mentors, avatars, and of course Fido. On the death of anyone else, Jews merely act like normal people.
- Traditionally, the period of mourning is seven days, no matter what you thought of the deceased. However, some Reform Jews observe a three-day shiva, and some can get it done in a matter of minutes.
If a high holy day occurs during a shiva, the shiva ends, and the participants can go straight home; they need not pass "Go" nor collect $200. Few Jews time their deaths to take advantage of this rule.
Speaking of collecting $200, one of the things you're not supposed to do during shiva is report to work. But there are dozens of grounds for a rabbi to excuse this requirement, such as when it might endanger public safety, or get you fired, and for stockbrokers who don't want to miss a big turn in the market.
After the formal end of the shiva, Jews are subject to other restrictions for either one month or one year. These prohibitions, designed to remind them that they are still miserable, include haircuts, new clothes, movies, and having fun. Some Orthodox Jews sit shiva after other horrible events, such as Junior dropping out of med school or dating a shikse.
Crashing a shiva
You can think of a shiva as a big party at the home of the mourner(s). But not all the party-goers are in the best of moods. On the one hand, someone close has died; on the other hand, all manner of distant friends and total strangers have come to the house for their own entertainment. And the tradition is that the visitors bring food to the host, not the other way around. However, you can sometimes get some leftovers. What you cannot do is take a hot shower or sit in a comfortable chair. Or, technically, have sex. For some people, this defeats the purpose of crashing a shiva.
On arriving at a shiva, the visitor does not initiate a conversation but takes cues from the mourner(s). This is because of the rules of shiva; also because crashing any party can be awkward. It helps to have several Yiddish phrases on the tip of your tongue. A typical ritual utterance is, "May you be comforted by Hashish." Or something. The mourner may share his grief with you, may remain silent, or may just stare and wonder, Do I know you?
As with the Tefillin, God doesn't just want you to wear specific things, but to mark them to make it clear you know you are wearing them, and someone didn't just put them on you as a joke. God can't just read your mind. The mourner sitting shiva must wear a torn piece of clothing called the keriah. The keriah must be torn for the occasion, not just some torn clothing you have lying around. The keriah requirement is not followed in Emo Judaism.
After shiva is over, you discard the keriah; you don't sew it back up, scavenge it for buttons, or take it to Goodwill Industries. You wouldn't dig Mother back up and sit her at the dinner table, would you?
Based on the many rabbinical rules that require the mourner to spend a period of several days being uncomfortable and putting it on display, many Jews actively contrive to avoid shiva. Some refer to shiva as torture. Visitors to a shiva do not care, as the desire in humans to get free food is so strong as to overwhelm the conscience.