In the late 60's they had an RA that they just absolutely hated.
After he went to bed, they built -- with real mortar and cement -- a brick wall in front of his door.
ND Fire Dept. had to come and extend a ladder to his window so he could get out.
No one ever fessed up & no one got in trouble -- I think the administration was just impressed with the organization and complexity of the prank that they let it go after some initial investigation.