Souvenir Edition

Or another way to sell papers. On a date of certain (good) historical significance, newspapers will stick in a supplement and declare themselves a "souvenir edition", although it's really just a normal paper with coverage of the event taking up a good ten or so pages.

Examples:
 * The election and the inauguration of Barack Obama.
 * New year's day, year 2000.
 * Local team wins a national title.

It should be pointed out that there is also a tendency for people to keep papers for historical events (good or bad) and there are a number of companies that will send you a copy of a particular paper for a particular date as a present for someone or yourself.