A bit of nostalgia - Commodore 64 meets modern kids

Or on the Amstrad CPC 464, you could do this:

10 FOR N=1 TO 58200
20 NEXT N
30 SOUND 1, 300, 50
40 GOTO 30

The above was a little routine I sometimes set off in Curries and the likes on their computers they had on display. Basically it says, give me 1 minute to walk away casually, then start annoyingly squealing indefinitely.