Tec-22. Besides not being able to find an actual use for the thing, the one I had was terribly inaccurate and highly unreliable.
Other than that, I'd say just about any of the Raven, Jennings, Lorcin, etc pocket-sized pistols in 25acp or 22LR. They may have had their place at one point in time, but today there are many quality pocket pistols in 9mm and 40 S&W, so there's no realyl good excuse for carrying an anemic cartridge.