This is a broad topic.
Any portable computer can be used to play at least some games.
Sony PSP ∞
Nintendo DS ∞
https://www.nintendo.com/3ds/ Nintendo DS Homepage
- There's a Nintendo DS Lite that's 1/3rd smaller and 20% lighter.
- The DS Wiki
- Nintendo DS Linux Forum
Fun Facts ∞
- Touchscreen brightness
: The touchscreen is only marginally dimmer than the top screen.
- Original Gameboy
Doesn't play old Gameboy black and white titles, just GBA.
The real reason GBC support was dropped was that the DMG/GBC ran on a 5 volt bus, whereas the GBA/DS run on a 3.3v bus. The GBC could easily have been emulated in software, much like the eReader does for the NES and (arguably) the DS does for the GBA (stepping the arm7 back, handling SWI calls according to a lookup grid, etc.) Adding 5-volt support would have meant using a rechargable battery which could handle both voltages, as was done in the SP. However, there are more efficient batteries which can only handle one voltage. It's not a cost issue. It's a battery life issue. Including 5v support would have shortened the battery live for 3.3v games unacceptably.
- A Nintendo Game Boy Emulator that will allow you to play the old Nintendo Handheld classics on your Gameboy Advance.
- The Gameboy SP lives on
Nintendo intends to make a second revision of the SP, and definitely will be maintaining both the SP and DS.
- Sleep mode
GBA games won't sleep when you close the lid, because the GBA hardware didn't support such a thing.
- GBA games and wireless
GBA games that used the optional wireless adapter will work with the DS's multiplayer functionality. However, link cable games will not.
Some will, others won't. It depends on which serial mode they're written to use and how sensitive they are to latency.
- Game Cube connectivity
There are in fact three ways already: 802.11b adapter, proprietary wifi protocol, or over the network
Tapwave Zodiac ∞
The Zodiac will run any game or application compatible with Palm OS 5. I'd really have to research Palm OS to figure out what it's capable of. This device does seem to have not insignificant potential..
Other stuff ∞
www.classicgaming.com/vcsp/ -- Whoa!