A lot of folks have been making fun of Senator Ted Stevens of Alaska for describing the Internet as not being like a truck, but being "made of tubes." As in, the things (he called what we presume was an email message an "internet") which we send each other on the Internet are put through something analogous to tubes in order to reach their destination.
(This is the guy who was roundly criticized for pushing the federal government to pay over $200 million for a "bridge to nowhere" in Alaska; a bridge to an island where 50 people, already amply served by a ferry, live. Turns out that bridge will no longer be built but Alaska is getting the money for it anyway, and their state legislature will decide what they do with it.)
The thing is, the tubes metaphor isn't a terrible one, especially for a guy who grew up watching silent movies. It's not really accurate, but in some ways it's better than "information superhighway," the metaphor people used before they stopped really needing a metaphor for the Internet, and where he probably got the truck comparison from.
A better metaphor is available from Roger Clarke, in his paper The Internet as a Postal Service: A Fairy Story. Worth reading, a quick read, and good for a layman who wants to know how things travel over the Internet.

ADD summary: the Internet is like a postal delivery system in which you pass your package (letter, book, movie, whatever) to a postal agent; they break it into lots of little pieces, and send each piece on its way to the destination you chose; those pieces find a random way through lots of other postal agents to their final destination; and if any piece gets lost, the folks at the final destination know to quickly ask you to replace just that small piece, and you can quickly send just that piece out again.
Though Clarke says "never, ever use it [his paper] as a basis for thinking about strategic or policy aspects of the Internet." Better to use his Primer on Internet Technology, which gets into nuts and bolts. (But - Application Layer Protocols? target-nodes? MTAs? A bit complicated for a senator...)
Anyway. The problem with Senator Stevens isn't that he thinks of the Internet as a bunch of tubes. The problem is that he thinks by voting against Net Neutrality, he will save the Internet for small folks, non-business folks, like you and me and him. Because in his misguided eyes, normal people don't try to clog the Internet's tubes with things like movies, music, and family pictures; businesses do, and unless the telcos build a two-tier Internet such that their multimedia content, email to their customers, etc. get priority in their new high-speed networks, their traffic will overwhelm all the things that ordinary folks like you and me are using the Internet for. Things like downloading movies and music and pictures and chatting. And sending email.
He doesn't realize - or he's pretending not to - that the likely result of Net Neutrality's death is slower service for people who don't pay twice to have their content delivered quickly. If I don't pay both my ISP and your ISP to let you see my website, my Halloween pictures will probably end up loading more slowly for you than pictures [from people - late edit] who've paid off your ISP. I'm already paying my ISP for bandwidth; now the telcos think everyone who wants to provide a service on the Internet should pay not only their own ISPs, but the ISPs of everyone they're trying to serve or reach.
That "internet" his staff sent him that took 3 days to reach him? Nothing to do with the Internet's tubes being full. The likeliest culprit is a problem with the mail server he's using on Capitol Hill.
Anyway, a round-up of people who're making fun of Stevens: The Daily Show, Annalee Newitz, BoingBoing.