Ultima Online account? If you did, then Mythic's new "Return to Britannia" campaign is aimed at you. All closed accounts in good standing have been reactivated, and will remain open until the 16th of October. Content up to and including the seventh expansion (Mondain's Legacy) will be playable by old accounts, which puts this offer in line with the 14-day free trials, with the added bonus of being able to play your previous characters.
The "Return to Britannia" campaign is part of the celebrations for Ultima Online's twelve-year anniversary, but keep in mind that the game's first expansion in years also launched earlier this month. Mythic Entertainment's Jeff Hickman made a statement about the offer: "UO was the first love of many MMORPG players, and it still holds a special place in their hearts after 12 glorious years. I think returning players will be pleasantly surprised to find a thriving and vibrant community from around the world ready to welcome back their former compatriots and include them in their ongoing adventures."
If you're keen to get back into UO, the client can be downloaded here, and Mythic is encouraging folks who can't remember their old details to try EA customer support.