Do you lay this down?

[Triumph36]

Just to chime in unneccesarily:

There are three hands that beat you, one of which he could legitimately have (66). There are several hands that could make this play (QT of hearts, KJ, K6, AK).

I think I have seen set over set once in live poker that I can remember, offhand I'd say the odds are 1/64 and that's even assuming the other guy has a pocket pair to begin with. I'd have to have a great read on a player to fold bottom set, especially if he's been check raising a lot.