Sometimes a magic lasso is just the best fashion accessory that one could ask for.
Today's knot is the Clove Hitch. This is a great and super easy way to tie a line. It's so unbelievably fast.
1) Pass the line around the post or bar or whatever.
2) Pass the line around the post on the other side of the standing end.
3) Feed the working end underneath the second loop.
4) Cinch the knot.
The things that you should keep in mind are: a) leave a bit line past the knot since it might slip a touch before catching b) if wiggling the standing part will loosen this knot.