Perhaps a racking cane or something? Would be similar I imagine to bottling from a carboy.
I decided to give this a go after discussing it with manticle at beerfest last week. I've never had a use for taps on my cubes, so they all have the bung covering where the tap would go.
I already had a batch in a cube from a while back and thought "i'll just tip it on it's side, remove the bung and attach the tap". That was until I removed the bung, didn't get any "pffft" as it sucked in air and realised there is a bit of plastic behind the bung! I didn't want to get bits of plastic in my beer, or risk infection by drilling through with a dirty drill, so my only option was to go and get a siphon. Haven't used one before and haven't used it yet, but I don't imagine it is particularly hard.
Before I brew my next batch, I'm going to be fitting all of my cubes with taps cause I can fit two cubes in my fermenting fridge and it means one less vessel to clean.
Thanks for discussing and posting this, Manticle. Good article.
There's a bottle or two of dark english mild for you when it's ready.