Much, much foreign money, most of it no longer legal tender since the introduction of the euro.
I’ve got a couple of big box frames and one day will actually sit down with a glue gun and make it look pretty enough to hang. Until then, it is in a big box under the sofa.
Our friend in Muscat sent us an Iraqi note with Saddam’s face on it- my huband has that pinned to the corkboard in his study.
The euros we keep for trips to the eurozone (Dublin and Donegal mostly).
I have… coins. Dating back to, eh, 1900. And an amount of paper bills from post-WWI to the modern day.
I should make a list.
You can all send your Canadian money to me if you like. 
We keep our USD when we return from the US since we go there fairly frequently - we always buy some more before we go, but it’s nice to have some smaller money than the twenties that we get from the CAA. I’ve been watching for the CAD to get significantly higher than the USD so I can go buy some more without taking a hit on the exchange fees (par is good, but par plus 10% is better).
I have fistfulls of the stuff. So much that I find it in coat pockets, when we vacume the house and in suitcases.
My passport holder has a pocket with my emergency funds in there - I leave extra from countries in there, and then when I go back I have some folding money to tide me over. It currently contains about $100 US in both rupees and Taiwanese Dollars, as well as 70 Euro, 60 UKP and $200 US.
There are various coins all over my house…
The only foreign country I’ve been to is Canada, and that was way before I married. I really have no desire to go out of the country now, so I have no money from actual trips. What little bit I have that I found in change I do keep, mainly to teach currency exchange rates to our kids.
My most unusual coins are two Jamaican dollars that one of my children found left in a Coinstar machine. Due to their size, it’s my guess someone thought they were dimes.
You’re rich! Well, not a millionaire, but a tenth of the way there!
I used to keep a leftover 5,000 Lira note in my wallet just to feel like a big shot.
(Yes I know how much that is in dollars, which is why it wasn’t worth my time to get to the bank and exchange it. But it amused me to look at it and go “Five thousand! That’s a lot! Wha-Hoo!”)
I actually have 100 Trillion Zimbabwe Dollars as well. 
Digging through my desk at home, I found:
1000 lira Italian note, maybe 300 Greek drachma in various coins, 200 Portuguese centavos, Og only knows how much in those tiny Swiss centime coins, 20 Austrian shillings, maybe 3 pounds in old English coinage, 300 Spanish pesatas, 4 dollars Canadian, 12 Mexican pesos, 20 centimes French, a Ugandan 10 cent piece, a 10 laari coin from the Maldives, a square 1 cent piece from old British Borneo and a bus token from the Anchorage City Transit System, circa 1960.
Yeah, it’s stupid and I don’t know why I do it, but every so often I find a random deutchemark or pound or forint or whatever. What, so people will know how smart and well traveled I am? I don’t know, can’t quite bear to throw them out.
I try to keep one or two of each coin type in every country I visit and maybe some of the smaller-value bills.
In some countries, such as Vietnam and Laos, you cannot reconvert the money, you’re just stuck with whatever is left over. I try to exchange carefully, but sometimes I’m just left with some by default.
Living in Thailand, the wife and I always keep a brand-new, mint-condition version of each new bill that comes out, even the largest one, the 1000-baht note (US$32.50 at today’s rate). Not that new ones come out all that often, but we have a pretty complete set stretching back to the 1980s. Even samples of some that have disappeared completely, such as the 10-baht note or the experimental plastic version of the 50-baht note.
When I was in Italy in 1999, my friends and I took pictures of ourselves with 20,000 lira notes, I think. I remember that they were worth about $40. Italy is really missing something now that they’re on the euro.
Hey..I did an OP about it..so yeah..probably that. 
I keep the Canadian stuff because I go there for work, and it’s nice to be able to buy a sandwich in the airport without using the credit card. The rest? I think I just don’t like to throw out money. I mean..it’s money!
-D/a
My husband travels a lot for business and I join him when I can. I don’t know how much we have but I think at any given time we usually have 20-50 US dollars, Euros and Pounds at home. And a 3$ Cuban tourist note because I like the idea of a 3$ bill!
Did I forget to mention the Nepalese coins I carry around just so I can pick up chicks at the driving range?
I have a bunch of change and notes from my travels and poker games. (While working at an English-language business paper in Europe before the introduction of the Euro, I occasionally hosted poker nights, and, with all the business reporters and currency geeks around, it quickly went from a one currency game to an “any currency goes” game, provided we all accepted the exchange rate.)
I figure it’s a fun souvenir (I don’t really buy any other souvenirs), plus kids like it as a curiosity. I don’t know how much of each I have, but I’d guess I have at least two or three dozen different currencies in my collection, most of which are no longer in use. My favorite was always the Dutch currency (guilder/gulden), particularly the 50 note.
American who used to live in Germany here. I’ve got a few Euro scattered around, a few pence (UK), probably a few Czech crown, about 700 Saddam era Iraqi dinar and 25,000 new Iraqi dinar.
And it actually has the entire numeral on it, not just “100 trillion dollars.” Impressive. As mentioned in the hyperinflation thread, the old Hungarian pengo denomination peaked at 100 quintillion (10^20), but they gave up on the zeroes after 100,000.
Pre-2005 Turkish lira were perhaps the most hyper-inflated currency a casual traveler would come across (or can you think of any others?) It peaked at 20,000,000 (also printed with all the zeroes), which I believe was worth about $20 before the change into the new Turkish lira.
I do keep foreign money as a “souvenir” of the places I’ve traveled. Most of what i bring home is in the form of bills, since those pesky coins are heavy.
I visited Guatemala about 20 years ago and have a ½-Quetzal note. It is a paper bill of denomination ½-Quetzal. Pretty money… I wonder if it is still made?
You also forgot to mention if it works..
-D/a
