Various and sundry things: Vikings, pickled herring, winegum candy (better known as swedish fish), swedish meatballs, the IKEA furniture company, the midnight supper meals, different musical groups such as ABBA, lingonberry jam, Swedish architecture, heavy uses of salt in food, different sorts of cake, pepparkaka (a type of gingerbread house), socialism (for better or for worse), egalitarianism stemming from a lack of serfdom in the middle ages, the city of Visby, Swedish literature (Astrid Lindgren, Selma Langerlof, August Strindberg, etc), the unique swedish traditional clothing, all different sorts of art, the Swedish accent (which I have due to being 1/4 Swedish and having family members that moved to America in the mid 20th century, I also have other weird factors affecting my accent), having a stereotypically much colder climate than it actually does (it's ranged from -64 Fahrenheit to 100 Fahrenheit, but it's more like Maine than Alaska), the midnight sun in the summer and the northern lights in winter, Ale's stones, the Stockholm Metro (including some monorails). And also, even though it's not Swedish, the Swedish Chef from the muppets. ^_^ There's lots more, but I thought a small sample would suffice.
Here's also a weird fact: In the first half of the 20th century, more Swedes lived in Chicago than in Gothenberg, the second largest city in Sweden (interestingly enough, Iowa City, where the Swedish branch of my family moved to after immigrating here (actually where most of my family lives, amazingly) isn't all that far away).
Sweden is one of those things I quite enjoy talking about, and something I studied extensively a few years ago until I learned all there is to learn about it. I'd also like to learn the Swedish language some day (although I know a few words and phrases here and there already, I want to actually learn the language).