Fung Wah, from Boston <-> NY for something like $15. For a while, it seemed like every week there was news of another Fung Wah accident, whether it be hitting the Mass Pike toll booths or tipping over on the on ramp. They should have advertised "$15 for an ADVENTURE"
Even better, there was a period of time (somewhere around 2003-2004 IIRC) when the CT police decided that shaking down the Fung Wah bus would be a great way to make their narcotics quota. Supposedly it was being used by drug mules. They were stopping the (northbound only?) busses just south of Sturbridge MA seemingly daily, and about once a week there'd be a story of "$LARGEQUANTITY of $NARCOTIC confiscated from Boston-NYC Bus".
I'm not quite sure what the MO of the drug transporters was; I never heard of any arrests so I think they must have been using it basically as a moving dead drop.
The few times I took it though were, sadly, uneventful. One lady did have a live chicken with her, but that was about it.