Short for Morf Transportation Incorporated, a taxi company in Burlington, Vermont. They can drive you around in standard sedans, limousines, and vans.
They are best known for their big white vans that carry drunk college students between the bars and the dorms. In fact, the term Morf has come to refer to these vans in particular (sometimes, it is even stretched to include any vehicle that functions as a taxi), rather than the actual company that operates them. So, it would be correct for one to respond to the question, "How are we going to get to the bar tonight?" like this, "Well, I'm not driving. Let's call a Morf!"
A ride in one of these things only costs $2 each way if you get 6 or more people together. Not a bad deal, considering that you also get entertainment (if you're on your way back from the bar, that is). If the driver is especially nice, he might even let you talk on his radio.
Also, keep an eye open for them in the Guinness Book of World Records, once such a category is created, they will probably hold the record for the most drunk college students crammed into a single vehicle.