Found a hose disconnected at the rear left of my engine bay. I loosened the screw on the jubilee style clip, slid it back over the metal tube it connected to and re-tightened it easily, however i have no idea what it is...

Sorry for the crappy pic (I had to turn up the brightness so you could actually see it)

 

Assuming the photo is of the left side of the engine near the rear of the engine compartment, those look like your fuel line supply and return hoses.

Edit: I need to read the posts better before posting. Yes, those are the fuel lines.

 

Top one (in your pic) is the looped pressurized fuel line, the one with the hose clamp is the vapor line to the carbon cannister. This pic shows it better:

 

Thanks Rob, yes (as above) its the left rear corner of the engine bay but its not a fuel line. I believe its been disconnected for some time.

Thanks garrett (sorry your post wasn't up yet when I typed the above). What does the vapor line do, just carry the vapor out of the car?

 

Oh yeah - you have a C2 so I think that top line is the vacuum line to the brake reservoir. Again, your picture sucks, but I am pretty sure that is what the one is without the hose clamp.

 

Yeah, that's what it is. This is a C2 that I worked on with my buddy - the top line is the fuel vapor line to the carbon cannister in the left rear wheel well, and the lower line is the vacuum source for the brakes.