Garbage bags are quite buoyant
The problem with having a leftover tank of helium in your garage on a public holiday is that you have to inflate things. Since I didn't have any balloons, the next best thing was garbage bags.
I inflated one, and to my surprise it was a lot more buoyant than I expected. I was planning on taking it out the back and expecting it to hover to about the second story balcony or something, instead it bounced off the eaves, and ascended into the heavens and was taken by a cross-wind off in the direction of Mount Majura, rapidly disappearing out of sight.
Sarah thinks I'm acting like a 12 year-old, but how many 12 year-olds have a tank of helium in their garage?
I do feel guilty about letting loose a flying garbage bag though... If it wasn't littering, I'd do it again so I could get some photos...