Good for unlimited travel for one person for a consecutive 24-hour period during operational hours. The 24-hour clock begins and the expiration date and time are stamped on the ticket with first use at the fare gates.(I got two last April when I was there for a trade show and ended up only using one. Its last day of validity is April 30th, 2009, so you must be going soon.)
Tickets are valid for one year from the date they're printed (shown in upper right corner).
Unlimited One-Day and Unlimited Three-Day Passes must be used within the 12 month period.
If you're near Boston I can get it to you. If you're not, it's probably not worth any kind of courier service, because it's a $9 pass. (Well, it was when I bought it, anyway. It's now $12, according to the website.) I'd like to have someone get to ride the monorail using it, so I'm offering it free.
If no one is actually going to use it for its intended purpose I'll just keep it as a souvenir. Our schedule probably won't get us there before it expires.