List of useful Commodore 64 poke and peek commands
Taken from "Computet's Gazette" and other sources

===== Screen codes =====
POKE 53272,21 switch to uppercase mode
POKE 53272,23 switch to lowercase mode
POKE 53280,C change border color (C=0-15)
POKE 53281,C change screen color (C=0-15)
POKE 646,C change cursor color (C=0-15)
POKE 53265,PEEK(53265) AND 23 turn off screen display
POKE 53265,PEEK(53265) OR 16 turn on screen display

===== Keyboard codes =====
POKE 650,128 all keys repeat
POKE 650,127 no keys repeat
POKE 650,0 normal repeat
POKE 657,128 disable SHIFT-Commodore
POKE 657,0 enable SHIFT-Commodore
POKE 198,0 clear keyboard buffer
POKE 649,1 disable keyboard buffering
POKE 649,0 disable keyboard
POKE 649,10 normal buffering
POKE 808,239 disable RUN/STOP key
POKE 792,193 disable RESTORE
POKE 808,239:POKE 792,193 disable RUN-STOP/RESTORE
POKE 808,234 disable RUN-STOP/RESTORE and LIST
POKE 808,237:POKE 792,71 enable RUN-STOP/RESTORE and LIST

===== And the rest =====
POKE 775,200 disable LIST
POKE 775,167 enable LIST
POKE 56341,S set cursor speed (S=0-255)
POKE 204,0 turn cursor on during a GET
POKE 204,255 turn cursor back off
POKE 19,65 turn off question mark during INPUT
POKE 19,0 turn question mark back on
POKE 54296,15:POKE 54296,0 make a click sound
poke 1,0 Disable Operating System (Default Value 1,1)
poke 198,0 Clear Keyboard Buffer
poke 198,0 Clears Keyboard Buffer (Default Value 198,0)
poke 22,35 Turns Off Line Numbers
poke 22,35 With List Command, Shows No Line Numbers
poke 53265,11 Turns Screen Off
poke 53265,27 Turns Screen On
poke 53272,21 Upper Case/Graphics
poke 53272,23 Upper Case/Lower Case
poke 56334,129 Clock Reset for 50 Cycle Current
poke 56590,128 Clock Reset for 50 Cycle Current
poke 649,0 Disable Keyboard
poke 649,10 Enable Keyboard
poke 649,15 Increase Keyboard Buffer
poke 650,0 Disable Repeat Function
poke 650,128 Enable Repeat Function
poke 650,64 Disables Repeat of All Keys
poke 774,0 With List Command, Shows Only Line Numbers
poke 774,141 With List Command, Vanishes Completely (Default Value 774,26)
poke 775,167 Enable List Command
poke 775,168 Disable List Command
poke 775,171 Causes Computer to Crash If a LIST Command is Attempted
poke 775,200 Disable List Command
poke 788,49 Enable Syop Key and TI$
poke 788,52 Disables Stop Key and TI$
poke 808,225 Disable Restore
poke 808,237 Enable Restore
poke 808,237 Restore Keyboard

===== sys commands =====
sys 57194 Re-activates EPYX Fastload
sys 58235 Warm Start
sys 58260 Initialize
sys 58726 CLR/HOME
sys 59062 Advance Cursor
sys 59137 Previous Line
sys 59626 Scrolls a Line
sys 59903 Clears Line of Text
sys 64738 Cold Start (Reset)
sys 65126 Alternate Start

===== Specialty commands =====
poke 792,peek(65532):poke 793,peek(65533)
Changes Restore Key to Reset
print peek(65408)
Test for Kernel Number
poke 808,225:poke 818,32 Disable Runstop/Restore
poke 808,237:poke 818,237 Enable Runstop/Restore
poke 56324,28:poke 56325,0 Slow List
poke 781,X:poke 782,Y:poke 783,0:sys 65520:Print"Your Message"
    Prints Your Message at X=ROW Number, Y=Column Number
poke 214,X:poke 211,Y:sys 58732:Print "Your Message"
    Prints Your Message at X=ROW Number, Y=Column Number