# The ol' sock on a doorknob

**URL:** <https://boards.straightdope.com/t/the-ol-sock-on-a-doorknob/938338>\
**Category:** In My Humble Opinion\
**Created:** [March 21, 2021, 3:03am UTC](https://boards.straightdope.com/t/the-ol-sock-on-a-doorknob/938338 "2021-03-21T03:03:06Z")\
**Posts on this page:** 3\
**Page:** 3

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**Author:** ![Bonum\_Legatum](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bonum_legatum/32/6183_2.png) [@Bonum\_Legatum](https://boards.straightdope.com/u/Bonum_Legatum)\
**Post date:** [March 26, 2021, 10:09am UTC](https://boards.straightdope.com/t/the-ol-sock-on-a-doorknob/938338/41 "2021-03-26T10:09:19Z")

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“Bag under the door” trick :Close the open end of the bag (press down on it with something straight, like a long ruler) and the person on the other side the door gets to have the bag burst open all over them.

If you are in a dorm of practical jokers, you’d know to keep a ruler handy.

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**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\
**Post date:** [March 26, 2021, 12:37pm UTC](https://boards.straightdope.com/t/the-ol-sock-on-a-doorknob/938338/42 "2021-03-26T12:37:42Z")

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> [@MikeF](#):
>
> Speaking of dorm hijinks, one could “penny in” someone in a room. We had heavy wooden doors in steel frames but here was a little give if you pushed on the door at, say, chest level. Pennies could be placed in this gap, stacked on edge, if you get my drift. You’d jam them in there so tightly that it was very hard to turn the knob with the latch bolt force up against the strike plate.

This happened to me in our dorm room my freshman year. Only it wasn’t a wooden door – we had a metal door in a metal frame. When you “penny” someone in that way, it’s serious. With wooden doors or jambs there’s some “give”, but metal doors and frames are solid.

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**Author:** ![MikeF](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@MikeF](https://boards.straightdope.com/u/MikeF)\
**Post date:** [March 26, 2021, 5:08pm UTC](https://boards.straightdope.com/t/the-ol-sock-on-a-doorknob/938338/43 "2021-03-26T17:08:09Z")

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I’d forgotten about the shaving cream trick, thanks. I witnessed it but never had it done to me. Another one was to cover the door opening (from the outside, of course) with newspaper. When the occupant would open the door to come out, they’d see wall of paper and kick or punch it out. What they didn’t see was the metal cabinet that had been placed in front of the door right up against the paper. No serious injuries and word got around pretty quick so people stopped falling for it.

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