When we were kids we used to say "bang bang, you're dead"

But now it's "bang bang, you're all icky."

For a while, the U.S. military worked and worked to develop a sticky foam that could stop rioters in their tracks. The goop never quite panned out - despite some rather hilarious pictures...

[From Army Reloads on Sticky Foam Weaponry | Danger Room from Wired.com]

OK, it didn't quite work - but they're still trying.