Not sure if this should be out of R&P but considering how this thread is light hearted, interesting and not written by...well the people in R&P, I shan't grumble
I'll summarise the rules we observe during Passover since I think that will give some context. Bear in mind I'm Jew-
ish (ie. secular/traditional as opposed to observant/religious). So we commemorate the Jews' exodus from Egypt and slavery when the tenth of the Ten Plagues sent by God finally convinced the Pharaoh to let them leave ("Let my people go!" and all that jazz). However since they had to leave in a hurry they didn't have the time to bake bread properly. As a result, we don't get to eat it for 8 days, all these years later ;-)
The basic gist is that we can't have anything
leavened or
fermented for those 8 days. The super-religious won't even touch anything processed (natural, or not at all). Leavened foods like bread, cake and their derivatives (eg. breadcrumbs) are out. Pasta too, since it "gets bigger" when it's cooked. Fermented things made from grains, like beer and whisky can't be drunk either. It's generally safest to just go "gluten free" for the time to be honest.
Beyond that, you probably know about Kosher food (similar to Halal for Muslims). Well the rules of Kashrut get knocked up a notch too. Normally, there's some leeway in "contamination" before something kosher becomes "traiff" (non-kosher). For example, you drop your bacon sandwich in the beef grinder...as long as the contaminant is less than 1/60th, it's still fine. At Passover however, that's out the window and it's zero tolerance. The observant empty their homes entirely of any breadcrumbs (it's actually a process itself, usually done by the kids as both a game and educational exercise) and "chametz" (non-"kosher for passover" things). They also use alternate crockery/cutlery (in addition to the normal two sets for meat/milk). Some super-religious go so far as to swap out/use a different cooker for the duration. The house is meant to be chametz free and is the reason most kosher restaurants/markets don't open at all for the whole time.
An aside while on the subject, "Kosher for Passover" is a level all to itself and indicates that something meets the higher standards Passover demands. In principle it works and works well, but it has given way to what I personally consider a rather under-handed "marketing" gimmick where everything gets labelled as such and gets an inflated price tag attached to boot. Such bullshit [http://www.frumsatire.net/2014/04/02/10-craziest-kosher-for-passover-products/] includes Kosher for Passover Cleaners and Detergents, Water, Masking Tape and toilet plungers.
Matzah is also its own thing. It's unleavened bread comprising only of wheatflour and water (no yeast). It's considered a "good thing" to eat it during Passover, though it can just be used as a snack/bread alternative. There are rules with them too, but things like cheeses, honey, jam, etc are all fine to have with (not during the ceremonies, but normally). Personally, I have the required amount at "the table" and barely any beyond that. Saying that, I do really like it with cold cuts like turkey breast and beef, or crumbly cheeses. I'll even have it like that any time of year.
For me personally, here is what I miss the most for those 8 days: Hamburgers (the bun), Twix bars (the biscuit), pasta of all sorts, KFC (breadcrumb), noodles (I get cravings for them sometimes!) and pizza. However, being an "eastern" Jew, I get to at least continue eating rice, unlike my "western" cousins (it's a tradition apparently...they're forbidden from eating rice for the same reason as pasta, "it gets bigger" when it's cooked) and can still enjoy meat, vegetables, potatoes (ie. chips), fish, dairy, etc.
One last point of interest which has led to many a discussion with other Jews I've met (both more and less religious than me). There are products that substitute for the things we lose out on for "Kosher for Passover" versions, like cake, pizza and so on. They are technically within the rules by no having any yeast and so on but I personally hate them (even as a non-religious person). As well as tasting sub-par, IMO while they are "within the letter of the law" they are not in keeping with "the spirit of the law" if that makes sense. It's like a cheat, a workaround based on a technicality. Hate it.
Hope that helped somewhat. Feel free to ask anything more as you like, happy to answer.
