Social gaming has become the hottest accessory to hit Hollywood since Yorkshire terrier puppies and house-arrest ankle bracelets.

Viacom's (NYSE: VIA)(NYSE: VIA-B) MTV Networks is acquiring game developer Social Express, according to tech blog VentureBeat. The deal comes just a week after Disney (NYSE: DIS) acquired Tapulous, the company behind Tap Tap Revenge and other rhythmic games. Tapulous was one of the early success stories through Apple's (Nasdaq: AAPL) App Store.

Viacom is no stranger to gaming itself. It's the company behind the Rock Band video-game franchise. However, its foray into casual gaming is new.

Social Express isn't a juggernaut along the lines of FarmVille parent Zynga or Electronic Arts' (Nasdaq: ERTS) recently acquired Playfish. Founded by a pair of former Zynga employees, Social Express expects to release its first casual games for Viacom as soon as this quarter. Turnaround times can be pretty quick when you're nimble and in a fast-changing industry where small, simple, yet addictive games rule.

It's just as well that Viacom is going for a small player. The media giant is apparently more interested in finding a capable developer to milk its cable properties for sticky online game fodder than overpaying for hot existing franchises. Terms of the deal weren't made public, though this is obviously a small deal compared to the $400 million that EA forked over for Playfish.

Social games have become popular through Facebook and smartphone apps, providing simple gameplay and interactive experiences. It's easy to see why media heavies are marking the territory. If folks are spending time on social games, they're not parked in front of their television sets watching cable.

Monetizing social games is the real challenge. Developers typically give away the games, hoping to more than recoup their costs through online advertising and selling virtual goods within the games.

We'll see whether Viacom's acquisitive appetite goes for another nibble in this space, but the trend of seeing media heavies snap up social-gaming companies is apparently just getting started.

Do you play social games? Share your favorites in the comments box below.