I think this counts as an exploit because it's unintended use of game mechanics or w/e. Anyway, I thought I'd share something my guild did back when I used to raid.
On Lady Vashj (SSC), during Phase 3 (the acid), Vashj AoE roots players randomly, usually this would mean they are stuck in the acid and need to rely on the healers to keep them up. Well theres a little trick for melee classes to get around this, while DPSing vashj all melee classes should spam jumping, that way when they are rooted in the air they aren't touching the ground and don't get hit by the acid. Its not a huge exploit but it definately helps out the healers.