Re: At University at Durham (and Newcastle)..
The other was that when a new year started, the initial passwords on the subsidiary computing students accounts were predictable, so you found one, but didn't change the password.
Queen's Belfast used to do a similar thing. A script allocated 200(?) new accounts at the beginning of the year, of the form "aaaannnn', and assigned passwords through a predictable algorithm. If there were only 160 new students that year you knew the alphabetically last 40 accounts & their resources were there for the taking by whoever changed the password first. After a while, most of the hackers had 10-20 extra accounts available.
As for "Colossal Cave" adventure, I once got summoned to the computer centre manager's office and shown a large pile of fanfold paper and asked if I knew what it was. A quick check showed it to be Colossal Cave adventure, from Jack Pike, which I had reworked to fit in the 25Kwords we engineering students were allowed. It was in my user directory, with the data file in one of the 'borrowed' accounts, from where a couple of friends and I (I thought) played it at break times. When I admitted I knew what it was, I was then asked why that one program accounted for 90% of billable computer time over the previous month... Apparently someone had told the CompSci students about it.
Somewhat to my surprise I was simply asked to restrict access to my friends & I, or it would be deleted.