Originally Posted by MagerValp
Just use a PAL C64 - all games work on PAL.
They'll "work".. but..
All the games will play slower.
The music would be at the wrong/slower tempo and all the notes will be off tune.
Many/most of his original NTSC games will not load.
None of his Commodore (170X/180x/108X) monitors will show a color picture if the are able to V-SYNC..
And if he's using a modern TV/LCD/Plasma, as a computer monitor, then odds are it won't sync or/and the picture will be B&W. in NA it's rare to find a TV that supports composite pal (except a few no-name cheap malmart ones)..
It's also not much fun taking a C=64 to a store so you can set it up and try each TV until you find one that can display PAL..