Greyhound
Details: Save 10% On Standard Fares with No Minimum Spend Required. Some restrictions may apply. Ends 5/31/13.
Metro-North Railroad
Details: Up to 60% off Regular Rail Fares for Groups of 30 or More. Restrictions Apply. See Merchant Site for Details
America by Rail
Details: $100 per person future tour credit
DART
Details: 25% off the best available room rate by presenting a DART Rail Day Pass.
The Port Authority of New York and New Jersey
Details: 10% off - not sure if it still works