I have a dollar bill from 1957 that says “silver certificate” on the front. In fact, it says, “This certifies that there is on deposit in the treasury of The United States of America one dollar in silver payable to the bearer on demand.”
I’m just tired enough to think that it would be kind of fun to walk into the Treasury building downtown and demand my dollar’s worth of silver.
Fun for the Treasury employees, anyway. 
You’d get more selling it to a collector. IIRC, when they introduced the Federal Reserve Notes, they “decommissioned” all the old silver certificates.
Besides, a dollar’s worth of silver is what…1/5 oz.?
Nice try, though.
A quick search shows that silenus is probably right: http://search.ebay.com//search/search.dll?from=R40&satitle=silver+certificate
Actually, Federal Reserve Notes were issued cponcurremtly with Silver Certificates for years. Several factors combined to spell the end of the Certificates’ era, as this page tells us:
Incidentally, in the above paragraph, “abolished” simply means “no longer issued”. It’s perfectly legal to own silver certificates – indeed, they’re still legal tender, although you’d be foolish to spend one when you could easily receive more than face value from a coin & currency collector or dealer.
Methinks I wasn’t clear enough: I know that the bill itself is worth more than a dollar, and that $1 of silver would, indeed, be a tiny amount. My point had nothing to do with money; the amusement came from picturing myself (or someone) walking into the Treasury with such currency and saying, “I want my silver!” 
Oh. Well then…
Nevermind.
On a similar note, I was given a bunch of old national geographics a few weeks ago. The original owner used an old subscription coupon for People as a bookmark. The coupon offers a subscription at $.75 an issue vs the usual 2.00. It doesn’t have an expiration date, so I’ve half considered mailing it in just to see what would happen.
You’ll have more to laugh about when you try to use a $2 bill at a place with only young workers.