While my friend was at my house, he accidentally deleted the save file for my Super Smash Bros Melee. To re-pay me, he is willing to let me copy the save data from his memory card so I can get back (mostly) everything I lost. But, is there a way to safely copy data over? And, if so, how?
Unless Super Smash Bros copy protects it's saves, most games don't, then you can easily copy the save between memory cards. Just insert the memory card with the save you want to copy into one of the two memory card slots on the GameCube and stick the other card in the other slot. Then boot the GameCube with no game disc in the drive. When the menu appears, move down on the left control stick to select "Memory Card" and then press the A button. Then select the game save you want to copy and press the A button. Select "Copy" from the menu and then confirm the operation by selecting "Yes". That's all you need to do.
If Super Smash Bros doesn't allow its saves to be copied then you'll have to use homebrew software to do the copy. If your GameCube hasn't already been modded, you can also use a Wii which is much easier to mod to run homebrew.