I used to go into Dixons
and go onto their display computers. I created a hobby which was "Change the Screensaver", which I played for a while before the staff finally worked out how to change the password themselves (computers didn't come with a remote back then :p). So I'd change the screensaver to a scrolling marquee and change the password on each machine.

It simply read "Buy me cheaper at Comet".
( Jeccius Steam Borderlands 2 junkie, Tue 9 Sep 2008, 18:58, 6 replies)

I like this
wish I'd thought of that ..

*click*
(TheWeeWitch hasn't been here much recently .., Tue 9 Sep 2008, 18:59, closed)

Mr Bin
used to go into dixons and write
10 print "spectrums are better"
20 goto 10
on the C64s
( Mrs Entity is in hiding., Tue 9 Sep 2008, 19:03, closed)

Basic rocks
I used to write stuff like

10 print "You're gay ";
20 goto 10
end

The beauty of this was it scrolled at an angle and they had to press escape to stop it. When they did, they were greeted with gay.

There were ways to add some code which disabled the Escape/Break key too, so they were doomed to a reset of the computer (oh noes!)
( Jeccius Steam Borderlands 2 junkie, Tue 9 Sep 2008, 19:06, closed)

There was also
the worlds first animated computer porno, making use of FOR...NEXT loops or whatever the equivalent was back then.

Output went something like

yes! [wait a second or two]
yes!, yes! [wait a second or two]
yes!, yes!, yes! [wait a second or two]
OOH BABY! [wait a second or two]
*spluffs*

I'd like to think a 90s ASCIIart CDC was involved as well on some versions.
( uberdeity Wondered why Owen Lars knew of the term "hell" on, Tue 9 Sep 2008, 19:36, closed)

when I were a lad...
We had none of this computer password nonsense! I used to draw amusing pictures of angry turtles on the pen testing areas in WH Smith. And I never ever put the lids back on the expensive marker pens.


Hah.
(powervator and NONE SHALL PASS, Tue 9 Sep 2008, 21:22, closed)

I think I've mentioned this before
10 PRINT "MARY HAS BEEN FUCKED" x "TIMES"
20 LET X=X+1
30 GOTO 10
RUN

Mary was the girlfriend of someone I didn't like. He'd walk past the TRS-80 at Radio Shack, see that the number was in the four digit range and go mental.

Good times.
( The Resident Loon Not a demographic. Do not measure., Tue 9 Sep 2008, 22:14, closed)