I feel like adding a little to the etf conversation - just info, not making any call on n.gas direction.
All the etfs tracking front month are still subject to a lot of decay during contango which makes them a poor play aside from short term. HNU/HND on TSX - 2x leverege with good volume are nice for intraday trading again, but not great ideas longer term (the decay is big in HNU right now, plus currency hedges effect performance). If you like playing with fire, you may be able to figure out a way to profit from contango through HND. GAS is a 1x leveraged fund on front month AECO gas (Alberta contracts) - this gives it some funny tracking characteristics if you're trying to play nymex spot, and contango is still a suck.
There is an ETF on the TSX called HUN - its a longer term 1x leveraged fund on n.gas - I have it in my head that its year forward jan contracts rolled in nov, but you'd have to look up and confirm. If you want a directional bet on n.gas for a length of time, this is a reasonable play (doesn't suffer from contango or leverage degridation). HUN looks like it does no volume, but it has dedicated mm algo so you can always move 10k blocks within a few cent spread.
One other option coming up, if looking for a corporate pure play, is the nat gas half of Encana being spun out.