Warning: This cheat involves editing a game file. Always make a backup of the file before proceeding.

Use a text editor to edit the "config.ini" file in the game directory. Add the following line to the end of the file:

bindc+DIK_GRAVE(console_showhide)

Then, press ~ while playing to bring up the console. Enter sv_cheats 1 to enable cheat mode, then enter one of the following codes at the console window to activate the corresponding cheat function.