It’s worth noting that the Cap’n was famous for building “blue boxes,” simple circuits that generated the in-band signaling tones for routing long-distance calls. These were not the DTMF tones discussed here. Almost all long-distance switches now use digital out-of-band signaling, making blue-boxes obsolete for wreaking havoc.
As sort-of said above, any genuine Western Electric touchtone phone (like these http://images.google.com/images?hl=en&q=western+electric+2500&gbv=2) will generate the pure tone of a column when 2 buttons in that column are pressed, and ditto for two buttons in a row. Pushing 2 buttons on a diagonal produces silence.
My brother has perfect pitch and can do it.