Fake is a fake memory clear program (Flash application, actually) for your 83+/84+ series graphing calculator.
It intercepts and accurately fakes all forms of resetting memory so that you can keep your programs and Flash applications intact when your teacher "resets" it. It hides all your variables until you enter a code you specify from anywhere in the TI-OS.
Download v0.2 here, which works on all 83+/83+SE/84+/84+SE calculators with OS 1.16 or higher (maybe even lower).
Update: this screws up the VAT somehow after you re-enable everything and I'm too lazy to look into it, so just reset RAM when you're done. You should be backing things up in the archive anyway, silly.
Update2: this doesn't behave properly on OS 2.53MP or above. You should downgrade to OS 2.43 or lower if you want to use this.
Fake works through a series of hooks which intercept keypresses and alter menus at appropriate times so it appears the calculator is reset.
Select the "Fake" application from the APPS menu and enter a combination of keypresses to use to "unlock" the application later.
Once you reset the calculator using any of the above methods (which are the only normal ones), Fake will hide all of your programs and Flash applications. How it does this depends on the reset method (if you chose to reset RAM, only programs in RAM are hidden, if you chose to reset apps, it will only hide Flash applications, etc.).
Once Fake is active, you can see that all variables are hidden from the APPS, PRGM, and Memory Management/Delete screens (which also shows the free RAM/ROM as maxed out).
To show all variables again, just enter the "unlock" combination from earlier at any point in the OS.