I'm not married, but when my colleague's husband proposed, he did it on a camping/fishing trip (he's a fly-fishing guide). He said he'd caught a fish, and asked her to walk upstream (in her waders) to get the net. Inside the net, he'd pre-placed a sign painted as a rainbow trout that had written on it "You're the catch of a lifetime. Will you marry me?" The males in our office thought it was corny, the women loved it.