A momputer is a computer that is idiot-proof, but specifically targeted to one's mother. In this sense, a momputer must support the following credentials: Redundancy, ease of use, pretty GUI (remember, mom's looking at it once in awhile), instructions and links to videos of what to do with the computer, and a lifeline between you (or the related person in question) and your (or their) mother.
As well, a momputer has nothing fancy; No overclocking, no water cooling, no pricey, bleeding-edge hardware or a need to maintain on a daily basis. It must be powerful enough for small flash games, and the occasional flash advertisement. First-time PC users should also have the default browser (or different, easier one) pre-supplied with an advertisement blocker, and for the especially typo-prone, a system-wide spellchecker may also be on call. Keeping things simple and budget will ensure you don't break the bank, and give your mother a PC she can do basic tasks with.
Examples of momputers from OEMs would include netbooks, nettops, budget desktop PCs and budget notebooks.
I bought my mother a momputer so I can keep in touch with her online. I would have her playing my games with me, since she's into that stuff, but her comprehension on how to maintain a gaming rig is is that of a pet rock.