Does this count?
I found this at a flea market a few months ago. It's obviously a Wii rip-off console, and it's as horrible as it looks. But hey, for a "console" (Does this even count as one?) that cost me €3,50 and came with all this stuff I can't be that mad at it, especially after how many laughs I got out of it. Seriously, the bootleg games on those two cartridges range from dull to so bad it's funny, to the point I seriously found myself laughing out loud at what ridiculous things these games kept throwing at me.
I know, it doesn't really count as a console, but I don't really have anything else. All consoles I own have been very successful. I'm planning on picking up a Wii U soon, and that would then be the least successful console in my collection. Besides, I've NEVER seen one at someone else's house (only a few times in department stores), so I guess it fits the bill
I also have a few unusual game console peripherals, such as the Pro Fighter X (Super Famicom), Magical Shop (Casio Loopy), Slide Controller (Nintendo DS), and Piano Controller (Nintendo DS).
Holy cow, that's a thing? I have to look into that. I can't seem to find it on eBay though, is it really that rare? (Sorry, I'm a huge sucker for weird hardware/peripherals.