And the standalone sentry machine-gun came out from Samsung a while back:

http://www.newlaunches.com/archives/samsung_develops_machine...

Forget the headcrabs -- what about those flying chainsaws in HL2?

Also: will the high school curriculum ever catch up? One of the wackiest 'long bets' offered:

"By the year 2150, over 50% of schools in the USA or Europe will require classes in defending against robot attacks." http://discuss.longbets.org/postlist.php?Cat=&Board=86