This is a random, useful, and small program I made to prevent people from messing around on your calculator.
NOTE: THIS DOESN'T MEAN PEOPLE WON'T BE ABLE TO DO THINGS ON YOUR CALCULATOR
The Program: Edit
:0→K :ClrHome :Lbl 1 :getKey→K :If K≠0 :Then :Disp "STAHP" :Goto 1 :Else :Goto 1
These two commands store 0 in the variable K, which is necessary for the program to work. ClrHome simply clears the home screen to make it look like it's a regular screen. Keep in mind that on the non-color versions, most people will notice the bar at the top right, and on both types, people will notice that there is no blinking rectangle where they usually type things.
This Lbl enables us to go back to this spot later in the program.
This checks to see what key (if any) the user is pressing.
:If K≠0 :Then :Disp "STAHP" :Goto 1 :Else :Goto 1
This is the main part of the program. Basically, what it does is it first checks if K (the key the user is pressing) is not 0, as in the user is indeed pressing a button. If so, it displays "STAHP", or any other crazy phrase you want to display to the user; it then goes back to the labeled 1. If not, it goes straight back to 1.