Shovelware is a term for all the unbelievably crappy games and software often found on sale in Wal-Mart's $3 bin.
Shovelware started off in the days of modems when it took hours on dial up to download a shitty shareware game. A bunch of fly by night companies got the brilliant idea to start ransacking Bulletin Board Systems of all their shareware and freeware installers and pressing them to CD-ROMs which were then sold in the backs of Computer Shopper.
Wait, what's Computer Shopper? Well, back in the dark ages before the internet, if you wanted to buy computer parts and there wasn't a nearby Comp USA, you were stuck with Computer Shopper, which was basically Google Shopping in a monthly magazine form. Each issue was about the size of a phone book and was comprised of 90 percent ads.
Most of the ads were just for your typical computer parts, like motherboards or keyboards, but in the back of Computer Shopper, where the ad rates were cheap was a pre-internet red light district of adult CD-ROMs and games.
This was also where shovelware CD-ROM ads were found.
For a nominal fee, anywhere from $10 to $200 (seriously), you could pay for a cd-rom or two filled with the absolute worst shareware games and apps, and occasionally a gem like the demo for Wolfenstein 3-D. Not having any competition from the Internet at the time, this business boomed for a short while.
Post Internet, the term shovelware was applied not to CD-ROM collections of crap, but to utterly shitty videogames based off of licensed properties like Dora the Explorer or Hannah Montana and usually sold at stores like Wal-Mart or Target for markdown prices. Usually such games come about in a manner similar to E.T. for the Atari 2600: a company spends mega dollars acquiring the rights to a popular franchise and then has no time or money left to actually make a playable game based on it.
Shareware games based not on children's movie and television licenses do exist as well, but are usually made to appeal to either hicks (Deer Hunter) or the elderly (Sudoku).
Possibly the most insulting kind of shovelware available at these fine retailers are crappy apps that copy the function of well known open source/freeware apps that are freely available on the internet. Often they're so badly made they'll actually wreak havoc on a user's operating system. Their target audience is pretty much anyone over the age of 65.