Atari 2600 clone with 128 built in games. Sadly there's no cart slot on this one. The first version is nearly identical to the Wonderboy. Comes in PAL and NTSC versions.
The TV Boy II seems to be the same story but in a PS1-like controller. I like the translucent shell. At least it looks cool.
TV Boy III (also called "Super TV Boy,") seems to have evolved back to more of a "clone." Still no cart slot which is too bad, as I want an el-cheapo 2600 clone so I can hack it and make a portable like Ben Heckdom (check out his awsome site here.) All three machines work off an emulator (so no blinking sprites) and are pretty common on Ebay, shouldn't cost you more than $20.