Grief Your Own Faction In The Deepholm Cave
If you are in the cave in Deepholm, the one with the Gyreworms, you can sometimes pick up a daily at the entrance of the cave called Underground Economy. This quest requires you to use Ricket's Tickers to blow up some rocks in the cave. These explosives also cause a knock-back if you are close to them. This knock-back also affects other players, not just yourself.
I was doing the daily to kill 10 Gyreworms when I saw another player killing everything in sight, I placed a bomb down, got him stuck behind a bunch of rocks, and forced him to hearth his way out.
BTW: If you are a rogue or a druid, these can be used without breaking your stealth.