hambleto once bubbled...
2 nights a week for four weeks followed by a whole weekend at a quary - two days of diving in springs
I took a PADI course that lasted two nights during the week, then two weekend days in the pool followed up by four open water dives. At the time I thought, "Well, I've done the resort course and that's not hard. How much more can there be to it?"
Some 50 dives later I recommend the two to four week curriculum to the people that I like.