The first day of Passover in 1836 was April 2nd.
Yes, they absolutely can. Since passover is seven days (or eight in the diaspora) it must occur at least once.
All over the world.
Shavuoth is the fiftieth day after the second day of Passover.
It is set on the table during the Passover seder (the first and second nights of passover).
Varies from year to year.
Arugula is an edible leaf and is kosher year round including Passover.
Trends can change in a year or even a second.
That depends on which year you're asking about.
Yes, for most sects of Judaism.
Passover falls in either March or April. This year (2011) it started April 18
The holiday of Pesach (Passover) is one of the most important holidays of the Jewish year.