Of special note are the rather limited import prevention measures on the Super Famicom and its games. With respect to the US and Japan, it is possible to play an SNES game on a Super Famicom, save for the fact that the blocky SNES cartridges won't fit into the SFC's cartridge slot. All that is needed in this case is a converter with a male SFC connector on one side and a female SNES connector on the other. It's also possible to cut out chunks of the case itself, but in this case it would probably be easier to get a converter or a US SNES. This is true for all versions of the SFC.
Playing SFC games on an SNES is much simpler, as the only import prevention device is a pair of small plastic tabs on the inside of the SNES's cartridge slot. There are cartridge converters to spare you the trouble of performing minor surgery (an SNES Game Genie will also serve well in this regard), but all that is required is a small pair of clippers. Simply push over the dust doors on the cartidge slot, and cut out the small grey tabs near either end of the cartridge connector. This is true for both versions of the SNES.
Importing/exporting games in or out of Europe is much less common, as Japan and the US both use NTSC graphical encoding, but Europe uses PAL encoding. For those who have dual-mode television sets, European games and systems can be treated exactly as Japanese games and systems insofar as connectors are concerned.