In Harry's 4th year - 1994 to be precise - the Ministry of Magic revives the Triwizard Tournament. Cribbing from that wiki article, it is a wizarding tradition dating back to 1294 and held every five years, with Hogwarts in England, Beauxbatons in the French Pyrenees and Durmstrang in Norway or Sweden rotating the hosting duties. Hogwarts students matriculate after 7 years of school and Beauxbatons students take their O.W.L.s after six years instead of five; assuming Durmstrang students follow a similar course of study, then every student to have graduated from any of those schools between 1294 and 17921, would have spent part of a year abroad, studying in the halls or on the grounds of a foreign institute.
Dumbledore gives significant speeches to the assembled students, as is his custom, one at the beginning of the year announcing the tournament and one after the conclusion. One of the themes he touches upon is the importance of building international ties, and particularly bonding and standing with your friends during trying times. As Exchange Student World states, the top 5 reasons for foreign exchange programs are:
- Personal development
- Get a “second family”
- Meet new friends from all around the world
- Learn a new language
- Experience a new culture
Aside from learning a new language2, these goals line up almost exactly with the expressed and observed goals and occurrences of the Triwizard Tournament in Harry Potter and the Goblet of Fire. That makes it the grandest, most elaborate and most extensive foreign exchange program in the wizarding and muggle worlds.
Oh, and aside from the dying as well.
1: The tournament was canceled after the 1792 tournament due to injuries. This is apparently a canon quote from HP&tGoF, but it is admittedly an odd year, proving that the tournament was not consistently held every five years. If it were, there would have been tournaments in 1789 and 1794, and none in 1792.
2: In typical fashion, every Durmstrang and Beuaxbatons student featured in both the book and the movie have a superior grasp of the English language than any English speaking school student has over another language. This is partially a storytelling conceit, as it allows JKR to keep the text of the books in English, Parseltounge or magic. But it also agrees with my limited experience with foreign exchange students visiting my own English speaking schools: nobody learned much language from their hosting duties and the exchangees primarily learned English slang and pop culture.